Abrasive article with microparticle-coated abrasive grains

ABSTRACT

According to various embodiment of the present disclosure, a bonded abrasive article precursor includes a curable composition. The curable composition includes a curative component. The curable composition further includes one or more resins. The curable composition further includes a plurality of shaped abrasive particles. The curable composition is curable in an amount of time in a range of from about 0.1 minutes to about 20 minutes at a temperature of about 25° C. to about 160° C.

BACKGROUND

Abrasive particles and abrasive articles including the abrasiveparticles are useful for abrading, finishing, or grinding a wide varietyof materials and surfaces in the manufacturing of goods. As such, therecontinues to be a need for improving the cost, performance, and ease ofmanufacturing abrasive articles.

SUMMARY OF THE DISCLOSURE

According to various embodiment of the present disclosure, a bondedabrasive article precursor includes a curable composition. The curablecomposition includes a curative component. The curable compositionfurther includes one or more resins. The curable composition furtherincludes a plurality of shaped abrasive particles. The curablecomposition is curable in an amount of time in a range of from about 0.1minutes to about 20 minutes at a temperature of about 25° C. to about160° C.

According to various embodiments of the present disclosure, a bondedabrasive article can include a cured product of a curable composition.The curable composition includes a curative component. The curablecomposition further includes one or more resins. The curable compositionfurther includes a plurality of shaped abrasive particles. The curablecomposition is curable in an amount of time in a range of from about 0.1minutes to about 20 minutes at a temperature of about 25° C. to about160° C.

According to various embodiments of the present disclosure, a method ofmaking a bonded abrasive article includes curing a curable composition.The curable composition includes a curative component. The curablecomposition further includes one or more resins. The curable compositionfurther includes a plurality of shaped abrasive particles. The curablecomposition is curable in an amount of time in a range of from about 0.1minutes to about 20 minutes at a temperature of about 25° C. to about160° C.

According to various embodiments of the present disclosure, a method ofusing an abrasive article includes moving the abrasive article withrespect to a surface contacted therewith, to abrade the surface. Thebonded abrasive article can include a cured product of a curablecomposition. The curable composition includes a curative component. Thecurable composition further includes one or more resins. The curablecomposition further includes a plurality of shaped abrasive particles.The curable composition is curable in an amount of time in a range offrom about 0.1 minutes to about 20 minutes at a temperature of about 25°C. to about 160° C.

There are many reasons to use the bonded abrasive article precursors ofthe present disclosure. For example, according to various embodiments,the bonded abrasive article precursors of the present disclosure can berapidly cured at low temperatures. This can make it much quicker toproduce bonded abrasive articles in comparison to conventional phenolicresin bonded abrasives, which require comparatively long cure times thatcan be around 10 hours and high temperatures. According to variousembodiments reactants in the curable composition can be rapidly cured,e.g., more than 95% of the reaction exotherm has been consumed in lessthan 20 minutes. According to further embodiments, curing can occurconcurrently with forming, such that the curable composition does notneed to be first placed in a mold and then transported to an oven forcuing.

BRIEF DESCRIPTION OF THE FIGURES

The drawings illustrate generally, by way of example, but not by way oflimitation, various embodiments discussed in the present document.

FIGS. 1A and 1B show shaped abrasive particles having a truncatedpyramidal shape, in accordance with various embodiments.

FIGS. 2A-2E show various embodiments of tetrahedral shaped abrasiveparticles, in accordance with various embodiments.

FIG. 3 shows a cylindrical shaped abrasive particle, in accordance withvarious embodiments.

FIG. 4 shows a bowtie shaped abrasive particle, in accordance withvarious embodiments.

FIG. 5 shows an elongated shaped abrasive particle, in accordance withvarious embodiments.

FIG. 6 shows another embodiment of an elongated shaped abrasiveparticle, in accordance with various embodiments.

FIG. 7 is a perspective view of a bonded abrasive article, in accordancewith various embodiments.

FIG. 8 is a sectional view of the bonded abrasive article of FIG. 7taken along line 2-2, in accordance with various embodiments.

FIG. 9 is a sectional perspective view of an apparatus for making thebonded abrasive article precursor according to various embodiments.

FIG. 10 is another sectional perspective view of the apparatus formaking the bonded abrasive article precursor according to variousembodiments.

DETAILED DESCRIPTION

Reference will now be made in detail to certain embodiments of thedisclosed subject matter, examples of which are illustrated in part inthe accompanying drawings. While the disclosed subject matter will bedescribed in conjunction with the enumerated claims, it will beunderstood that the exemplified subject matter is not intended to limitthe claims to the disclosed subject matter.

Throughout this document, values expressed in a range format should beinterpreted in a flexible manner to include not only the numericalvalues explicitly recited as the limits of the range, but also toinclude all the individual numerical values or sub-ranges encompassedwithin that range as if each numerical value and sub-range is explicitlyrecited. For example, a range of “about 0.1% to about 5%” or “about 0.1%to 5%” should be interpreted to include not just about 0.1% to about 5%,but also the individual values (e.g., 1%, 2%, 3%, and 4%) and thesub-ranges (e.g., 0.1% to 0.5%, 1.1% to 2.2%, 3.3% to 4.4%) within theindicated range. The statement “about X to Y” has the same meaning as“about X to about Y,” unless indicated otherwise. Likewise, thestatement “about X, Y, or about Z” has the same meaning as “about X,about Y, or about Z,” unless indicated otherwise.

In this document, the terms “a,” “an,” or “the” are used to include oneor more than one unless the context clearly dictates otherwise. The term“or” is used to refer to a nonexclusive “or” unless otherwise indicated.The statement “at least one of A and B” has the same meaning as “A, B,or A and B.” In addition, it is to be understood that the phraseology orterminology employed herein, and not otherwise defined, is for thepurpose of description only and not of limitation. Any use of sectionheadings is intended to aid reading of the document and is not to beinterpreted as limiting; information that is relevant to a sectionheading may occur within or outside of that particular section.

In the methods described herein, the acts can be carried out in anyorder without departing from the principles of the disclosure, exceptwhen a temporal or operational sequence is explicitly recited.Furthermore, specified acts can be carried out concurrently unlessexplicit claim language recites that they be carried out separately. Forexample, a claimed act of doing X and a claimed act of doing Y can beconducted simultaneously within a single operation, and the resultingprocess will fall within the literal scope of the claimed process.

The term “about” as used herein can allow for a degree of variability ina value or range, for example, within 10%, within 5%, or within 1% of astated value or of a stated limit of a range, and includes the exactstated value or range.

The term “substantially” as used herein refers to a majority of, ormostly, as in at least about 50%, 60%, 70%, 80%, 90%, 95%, 96%, 97%,98%, 99%, 99.5%, 99.9%, 99.99%, or at least about 99.999% or more, or100%.

The polymers described herein can terminate in any suitable way. Invarious embodiments, the polymers can terminate with an end group thatis independently chosen from a suitable polymerization initiator, —H,—OH, a substituted or unsubstituted (C₁-C₂₀)hydrocarbyl (e.g.,(C₁-C₁₀)alkyl or (C₆-C₂₀)aryl) interrupted with 0, 1, 2, or 3 groupsindependently selected from —O—, substituted or unsubstituted —NH—, and—S—, a poly(substituted or unsubstituted (C₁-C₂₀)hydrocarbyloxy), and apoly(substituted or unsubstituted (C₁-C₂₀)hydrocarbylamino).

According to various embodiments of the present disclosure, a bondedabrasive article can be formed, at least in part, from a bonded abrasivearticle precursor. The bonded abrasive article precursor can include acurable composition that is capable of being cured in a time frameranging from about 0.1 minutes to about 20 minutes, 0.5 minutes to about15 minutes, 1 minute to about 10 minutes, less than, equal to, orgreater than about 0.5 minutes, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5,6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 10.5, 11, 11.5, 12, 12.5, 13, 13.5,14, 14.5, 15, 15.5, 16, 16.5, 17, 17.5, 18, 18.5, 19, 19.5, or about 20minutes. In addition to the rapid rate of curing, the curablecomposition is capable of curing at a low temperature such as roomtemperature, or at a temperature in a range of from about 25° C. toabout 160° C., about 100° C. to about 150° C., less than, equal to, orgreater than about 25° C., 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36,37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54,55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 80, 81,82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99,100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113,114, 115, 116, 117, 118, 119, 120, 121, 122, 123, 124, 125, 126, 127,128, 129, 130, 131, 132, 133, 134, 135, 136, 137, 138, 139, 140, 141,142, 143, 144, 145, 146, 147, 148, 149, 150, 151, 152, 153, 154, 155,156, 157, 158, 159, or about 160° C. According to various embodiments,the curable composition can be an epoxy composition, a polyacrylatecomposition, or a polyurethane composition. Although epoxy compositions,polyacrylate compositions, and polyurethanes compositions are mentioned,it is possible to have any other suitable curable composition in thebonded abrasive articles described herein.

The curable composition can include any number of components. Forexample, the curable composition can include one or more curativecomponents as well as one or more resins that are capable of being curedby the curable component. The curable composition can further includeone or more abrasive particles disposed therein.

The curative component can be in a range of from about 0.1 wt % to about40 wt % of the curable composition about 0.1 wt % to about 10 wt %, lessthan, equal to, or about 0.1 wt %, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5,5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 10.5, 11, 11.5, 12, 12.5,13, 13.5, 14, 14.5, 15, 15.5, 16, 16.5, 17, 17.5, 18, 18.5, 19, 19.5,20, 20.5, 21, 22, 22.5, 23, 23.5, 24, 24.5, 25, 25.5, 26, 26.5, 27,27.5, 28, 28.5, 29, 29.5, 30, 30.5, 31, 31.5, 32, 32.5, 33, 33.5, 34,34.5, 35, 35.5, 36, 36.5, 37, 37.5, 38, 38.5, 39, 39.5, or about 40 wt%. The curative component can be generally classified as a catalyst,linker, or extender. Specific, non-limiting examples, of curativecomponents include an acid catalyst (e.g., a Lewis acid), a basecatalyst (e.g., a Lewis base), an amphoteric catalyst (e.g., a catalystcapable of being a Lewis acid or a Lewis base). Further specificexamples of curative components include, an aliphatic polyamine, anaromatic polyamine, an aromatic polyamide, an alicyclic polyamine, apolyamine, a polyamide, an amino resin, a 9,9-bis(aminophenyl)fluorene,a polyisocyanate, a polyol chain extender. Examples of acid catalystsinclude antimony hexafluoride, a diazonium salt, an idonium salt, asulfonium salt, a ferrocenium salt, or a mixture thereof. Examples ofbase catalysts include an imidazole, a dicyandiamide an amine-functionalcatalyst, a compound including reactive —NH groups or reactive —NR¹R²groups wherein R¹ and R² are independently H or (C₁ to C₄)alkyl, or —H,methyl or a mixture thereof. In some circumstances the imidazole,dicyandiamide, or both can be amphoteric.

Examples of a polyisocyanate can includedicyclohexylmethane-4,4′-diisocyanate, isophorone diisocyanate,hexamethylene diisocyanate, 1,4-phenylene diisocyanate, 1,3-phenylenediisocyanate, m-xylylene diisocyanate, tolylene-2,4-diisocyanate,toluene 2,4-diisocyanate, tolylene-2,6-diisocyanate, poly(hexamethylenediisocyanate), 1,4-cyclohexylene diisocyanate,4-chloro-6-methyl-1,3-phenylene diisocyanate, hexamethylenediisocyanate, toluene diisocyanate, diphenylmethane 4,4′-diisocyanate,1,4-diisocyanatobutane, 1,8-diisocyanatooctane, or a mixture thereof.

Examples of suitable 9,9-bis(aminophenyl)fluorene compounds include9,9-bis(4-aminophenyl)fluorene, 4-methyl-9,9-bis(4-aminophenyl)fluorene,4-chloro-9,9-bis(4-aminophenyl)fluorene,2-ethyl-9,9-bis(4-aminophenyl)fluorene,2-iodo-9,9-bis(4-aminophenyl)fluorene,3-bromo-9,9-bis(4-aminophenyl)fluorene,9-(4-methylaminophenyl)-9-(4-ethylaminophenyl)fluorene,1-chloro-9,9-bis(4-aminophenyl)fluorene,2-methyl-9,9-bis(4-aminophenyl)fluorene,2,6-dimethyl-9,9-bis(4-aminophenyl)fluorene,1,5-dimethyl-9,9-bis(4-aminophenyl)fluorene,2-fluoro-9,9-bis(4-aminophenyl)fluorene,1,2,3,4,5,6,7,8-octafluoro-9,9-bis(4-aminophenyl)fluorene,2,7-dinitro-9,9-bis(4-aminophenyl)fluorene,2-chloro-4-methyl-9,9-bis(4-aminophenyl)fluorene,2,7-dichloro-9,9-bis(4-aminophenyl)fluorene,2-acetyl-9,9-bis(4-aminophenyl)fluorene,2-methyl-9,9-bis(4-methylaminophenyl)fluorene,2-chloro-9,9-bis(4-ethylaminophenyl)fluorene,2-t-butyl-9,9-bis(4-methylaminophenyl)fluorene,9,9-bis(3-methyl-4-aminophenyl)fluorene,9-(3-methyl-4-aminophenyl)-9-(3-chloro-4-aminophenyl)fluorene,9-bis(3-methyl-4-aminophenyl)fluorene,9,9-bis(3-ethyl-4-aminophenyl)fluorene,9,9-bis(3-phenyl-4-aminophenyl)fluorene,9,9-bis(3,5-dimethyl-4-methylaminophenyl)fluorene,9,9-bis(3,5-dimethyl-4-aminophenyl)fluorene,dimethyl-4-methylaminophenyl)-9-(3,5-dimethyl-4-aminophenyl)fluorene,9-(3,5-diethyl-4-aminophenyl)-9-(3-methyl-4-aminophenyl)fluorene,1,5-dimethyl-9,9-bis(3,5-dimethyl-4-methylaminophenyl)fluorene,9,9-bis(3,5-diisopropyl-4-aminophenyl)fluorene,9,9-bis(3-chloro-4-aminophenyl)fluorene,9,9-bis(3,5-dichloro-4-aminophenyl)fluorene,9,9-bis(3,5-diethyl-4-methylaminophenyl)fluorene,9,9-bis(3,5-diethyl-4-aminophenyl)fluorene, and a mixture thereof.

Examples of suitable polyol chain extenders include ethylene glycol, apoly(ethylene glycol), diethylene glycol, triethylene glycol,tetraethylene glycol, propylene glycol, a poly(propylene glycol),dipropylene glycol, tripropylene glycol, 1,3-propanediol,1,3-butanediol, 1,4-butanediol, neopentyl glycol, 1,6-hexanediol,1,4-cyclohexanedimethanol, or a mixture thereof.

In the curable composition, the one or more resins can be in a range offrom about 20 wt % to about 99.9 wt % of the curable composition, about25 wt % to about 70 wt % of the curable composition, less than, equalto, or greater than about 25 wt %, 25.5, 26, 26.5, 27, 27.5, 28, 28.5,29, 29.5, 30, 30.5, 31, 31.5, 32, 32.5, 33, 33.5, 34, 34.5, 35, 35.5,36, 36.5, 37, 37.5, 38, 38.5, 39, 39.5, 40, 40.5, 41, 41.5, 42, 42.5,43, 43.5, 44, 44.5, 45, 45.5, 46, 46.5, 47, 47.5, 48, 48.5, 49, 49.5,50, 50.5, 51, 51.5, 52, 52.5, 53, 53.5, 54, 54.5, 55, 55.5, 56, 56.5,57, 57.5, 58, 58.5, 59, 59.5, 60, 60.5, 61, 61.5, 62, 62.5, 63, 63.5,64, 64.5, 65, 65.5, 66, 66.5, 67, 67.5, 68, 68.5, 69, 69.5, or about 70wt %. The curable resins can include an epoxy resin, an acrylated epoxyresin, a polyester polyol, or a mixture thereof. In various embodimentsthe polyisocyanate, the polyol, or a mixture thereof may also beconsidered as a curable resin.

In embodiments where the curable resin includes one or more epoxy resinsexamples of epoxy resins can include a diglycidyl ether of bisphenol F,a low epoxy equivalent weight diglycidyl ether of bisphenol A, a liquidepoxy novolac, a liquid aliphatic epoxy, a liquid cycloaliphatic epoxy,a 1,4-cyclohexandimethanoldiglycidylether,3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexane carboxylate,tetraglycidylmethylenedianiline,N,N,N′,N′-tetraglycidyl-4,4′-methylenebisbenzenamine, a triglycidyl ofpara-aminophenol, N,N,N′,N′-tetraglycidyl-m-xylenediamine, an acrylatedepoxy resin, and a mixture thereof.

In embodiments in which the epoxy resin includes an acrylated epoxyresin, the epoxy resin can include a tetrahydrofurfuryl (THF)(meth)acrylate copolymer component, one or more epoxy resins (such asthose disclosed herein), and one or more hydroxy-functional polyethers.According to various embodiments, the THF (meth)acrylate copolymercomponent can be in a range of from about 15 to about 50 parts byweight, about 20 to about 40 parts by weight, less than, equal to, orgreater than about 15, 20, 25, 30, 35, 40, 45, or 50 parts by weight.The one or more epoxy resins can be in a range of from about 25 to about50 parts by weight, about 20 to about 40 parts by weight, less than,equal to, or greater than about 15, 20, 25, 30, 35, 40, 45, or 50 partsby weight. According to various embodiments, the hydroxy-functionalpolyethers can be in a range of from about 5 to about 15 parts byweight, about 7 to about 10 parts by weight, less than, equal to, orgreater than about 5 parts by weight, 6, 7, 8, 9, 10, 11, 12, 13, 14, orabout 15 parts by weight. According to various embodiments, in which theepoxy resin includes an acrylated epoxy resin, the acrylated epoxy resincan include one or more hydroxyl-containing film-forming polymers, whichcan range from about 10 to about 25 parts by weight, about 15 to about20 parts by weight, less than, equal to, or greater than about 10 partsby weight, 15, 20, or about 25 parts by weight. According to variousembodiments in which the epoxy resin includes an acrylated epoxy resin,the acrylated epoxy resin can include one or more photoinitiators, whichcan range from about 0.1 to about 5 parts by weight, about 1 to about 3parts by weight, less than, equal to, or greater than about 0.1 parts byweight, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, or about 5 parts by weight.

The THF (meth)acrylate copolymer component can include one or more THF(meth)acrylate monomers, one or more Ci-Cs (meth)acrylate estermonomers, and one or more optional cationically reactive functional(meth)acrylate monomers. The tetrahydrofurfuryl (meth)acrylate monomerscan be in a range of from about 40 wt % to about 60 wt % of the THF(meth)acrylate copolymer component, about 50 wt % to about 55 wt %, lessthan, equal to, or greater than about 40 wt %, 41, 42, 43, 44, 45, 46,47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, or about 60 wt %.The one or more Ci-Cs (meth)acrylate ester monomers can be in a range offrom about 40 wt % to about 60 wt % of the THF (meth)acrylate copolymercomponent, about 50 wt % to about 55 wt %, less than, equal to, orgreater than about 40 wt %, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51,52, 53, 54, 55, 56, 57, 58, 59, or about 60 wt %. The cationicallyreactive functional (meth)acrylate monomers can be in a range of from 0wt % to about 10 wt % of the THF (meth)acrylate copolymer component,about 2 wt % to about 5 wt %, less than, equal to, or greater than about0 wt %, 1, 2, 3, 4, 5, 6, 7, 8, 9, or about 10 wt %.

In embodiments, where the one or more resins include a polyester polyol,the polyester polyol can include polyglycolic acid, polybutylenesuccinate, poly(3-hydroxybutyrate-co-3-hydroxyvalerate), polyethyleneterephthalate, polybutylene terephthalate, polytrimethyleneterephthalate, polyethylene naphthalate, poly(1,4-butylene adipate),poly(1,6-hexamethylene adipate), poly(ethylene-adipate), mixturesthereof, or copolymers thereof.

The abrasive particles of the bonded abrasive article precursor caninclude shaped abrasive particles, crushed or conventional abrasiveparticles, or mixtures thereof For example, FIGS. 1A and 1B show shapedabrasive particles 100, which are generally triangular shaped abrasiveparticles. As shown in FIGS. 1A and 1B, shaped abrasive particle 100includes a truncated regular triangular pyramid bounded by a triangularbase 102, a triangular top 104, and plurality of sloping sides 106A,106B, 106C connecting triangular base 102 (shown as equilateral althoughscalene, obtuse, isosceles, and right triangles are possible) andtriangular top 104. Slope angle 108 is the dihedral angle formed by theintersection of side 106A with triangular base 102. Similarly, slopeangles 108B and 108C (both not shown) correspond to the dihedral anglesformed by the respective intersections of sides 106B and 106C withtriangular base 102. In the case of shaped abrasive particle 100, all ofthe slope angles have equal value. In various embodiments, side edges110A, 110B, and 110C have an average radius of curvature in a range offrom about 0.5 μm to about 80 μm, about 10 μm to about 60 μm, or lessthan, equal to, or greater than about 0.5 μm, 5, 10, 15, 20, 25, 30, 35,40, 45, 50, 55, 60, 65, 70, 75, or about 80 μm.

In the embodiment shown in FIGS. 1A and 1B, sides 106A, 106B, and 106Chave equal dimensions and form dihedral angles with the triangular base102 of about 82 degrees (corresponding to a slope angle of 82 degrees).However, it will be recognized that other dihedral angles (including 90degrees) may also be used. For example, the dihedral angle between thebase and each of the sides may independently range from 45 to 90 degrees(for example, from 70 to 90 degrees, or from 75 to 85 degrees). Edgesconnecting sides 106, base 102, and top 104 can have any suitablelength. For example, a length of the edges may be in a range of fromabout 0.5 μm to about 2000 μm, about 150 μm to about 200 μm, or lessthan, equal to, or greater than about 0.5 μm, 50, 100, 150, 200, 250,300, 350, 400, 450, 500, 550, 600, 650, 700, 750, 800, 850, 900, 950,1000, 1050, 1100, 1150, 1200, 1250, 1300, 1350, 1400, 1450, 1500, 1550,1600, 1650, 1700, 1750, 1800, 1850, 1900, 1950, or about 2000 μm.

Although FIGS. 1A and 1B show triangular shaped abrasive particles 100,there are many other suitable examples of shaped abrasive particles thatmay be included in bonded abrasive article precursor. For example,bonded abrasive article precursor can include tetrahedral shapedabrasive particles. FIGS. 2A-2E show various embodiments of tetrahedralshaped abrasive particles 200. As shown in FIGS. 2A-2E, shaped abrasiveparticles 200 are shaped as regular tetrahedrons. As shown in FIG. 2A,shaped abrasive particle 200A has four faces (220A, 222A, 224A, and226A) joined by six edges (230A, 232A, 234A, 236A, 238A, and 239A)terminating at four vertices (240A, 242A, 244A, and 246A). Each of thefaces contacts the other three of the faces at the edges. While aregular tetrahedron (e.g., having six equal edges and four faces) isdepicted in FIG. 2A, it will be recognized that other shapes are alsopermissible. For example, tetrahedral abrasive particles 200 can beshaped as irregular tetrahedrons (e.g., having edges of differinglengths).

Referring now to FIG. 2B, shaped abrasive particle 200B has four faces(220B, 222B, 224B, and 226B) joined by six edges (230B, 232B, 234B,238B, and 239B) terminating at four vertices (240B, 242B, 244B, and246B). Each of the faces is concave and contacts the other three of thefaces at respective common edges. While a particle with tetrahedralsymmetry (e.g., four rotational axes of threefold symmetry and sixreflective planes of symmetry) is depicted in FIG. 3B, it will berecognized that other shapes are also permissible. For example, shapedabrasive particles 200B can have one, two, or three concave faces withthe remainder being planar.

Referring now to FIG. 2C, shaped abrasive particle 200C has four faces(220C, 222C, 224C, and 226C) joined by six edges (230C, 232C, 234C,236C, 238C, and 239C) terminating at four vertices (240C, 242C, 244C,and 246C). Each of the faces is convex and contacts the other three ofthe faces at respective common edges. While a particle with tetrahedralsymmetry is depicted in FIG. 2C, it will be recognized that other shapesare also permissible. For example, shaped abrasive particles 200C canhave one, two, or three convex faces with the remainder being planar orconcave.

Referring now to FIG. 2D, shaped abrasive particle 200D has four faces(220D, 222D, 224D, and 226D) joined by six edges (230D, 232D, 234D,236D, 238D, and 239D) terminating at four vertices (240D, 242D, 244D,and 246D). While a particle with tetrahedral symmetry is depicted inFIG. 2D, it will be recognized that other shapes are also permissible.For example, shaped abrasive particles 200D can have one, two, or threeconvex faces with the remainder being planar.

Deviations from the depictions in FIGS. 2A-2D can be present. An exampleof such a shaped abrasive particle 200 is depicted in FIG. 2E, showingshaped abrasive particle 200E, which has four faces (220E, 222E, 224E,and 226E) joined by six edges (230E, 232E, 234E, 238E, and 239E)terminating at four vertices (240E, 242E, 244E, and 246E). Each of thefaces contacts the other three of the faces at respective common edges.Each of the faces, edges, and vertices has an irregular shape.

In any of shaped abrasive particles 200A-200E, the edges can have thesame length or different lengths. The length of any of the edges can beany suitable length. As an example, the length of the edges can be in arange of from about 0.5 μm to about 2000 μm, about 150 μm to about 200μm, or less than, equal to, or greater than about 0.5 μm, 50, 100, 150,200, 250, 300, 350, 400, 450, 500, 550, 600, 650, 700, 750, 800, 850,900, 950, 1000, 1050, 1100, 1150, 1200, 1250, 1300, 1350, 1400, 1450,1500, 1550, 1600, 1650, 1700, 1750, 1800, 1850, 1900, 1950, or about2000 μm. Shaped abrasive particles 200A-200E can be the same size ordifferent sizes.

In other embodiments, shaped abrasive particles may be shaped as acylinder as shown in FIG. 3. FIG. 3 is a perspective view showing shapedabrasive particle 300. Shaped abrasive particle 300 includes acylindrically shaped body 302 extending between circular first andsecond ends 304 and 306.

In other embodiments, shaped abrasive particles may be shaped to have abowtie shape as shown in FIG. 4. FIG. 4 is a perspective view ofabrasive particle 400. Abrasive particle 400 includes elongated body402, which is defined between opposed first end 404 and second end 406,having axis 410 extending through each end. An aspect ratio of a lengthto a width of abrasive particle 400 can range from about 3:1 to about6:1, or from about 4:1 to about 5:1.

Axis 410 extends through the middle of elongated body 402, first end404, and second end 406. As illustrated, axis 410 is a non-orthogonalaxis, but in other embodiments, axis 410 can be a straight axis. Asillustrated, each of first end 404 and second end 406 define asubstantially planar surface. Both first end 404 and second end 406 areoriented at an angle relative to axis 410 that is less than 90 degrees,and each end is non-parallel with respect to each other. In otherembodiments, only one of first and second ends 404 and 406 are orientedat an angle relative to axis 410 that is less than 90 degrees. First end404 and second end 406 have respective first and second cross-sectionalareas. As illustrated, the first and second cross-sectional areas aresubstantially the same. But in other embodiments, the first and secondcross-sectional areas can be different. Elongated body 402 tapers inwardfrom first end 404 and second end 406 to a mid-point having across-sectional area that is smaller than that of first or second ends404 and 406.

In other embodiments, as shown in FIG. 5, shaped abrasive particle 500has an elongate shaped ceramic body 502 having opposed first and secondends 504, 506 joined to each other by longitudinal sidewalls 508, 510.Longitudinal sidewall 508 is concave along its length. First and secondends 504 and 506 are fractured surfaces.

In other embodiments, as shown in FIG. 6, shaped abrasive particle 600has an elongate shaped ceramic body 602 having opposed first and secondends 604, 606 joined to each other by longitudinal sidewalls 608 and610. Longitudinal sidewall 608 is concave along its length. First andsecond ends 604, 606 are fractured surfaces. Shaped abrasive particles500 and 600 have an aspect ratio of at least 2. In various embodiments,shaped abrasive particles 500 and 600 have an aspect ratio of at least4, at least 6, or even at least 10.

Any of shaped abrasive particles 100, 200, 300, 400, 500, or 600 caninclude any number of shape features. The shape features can help toimprove the cutting performance of any of shaped abrasive particles 100,200, 300, 400, 500, or 600. Examples of suitable shape features includean opening, a concave surface, a convex surface, a groove, a ridge, afractured surface, a low roundness factor, or a perimeter comprising oneor more corner points having a sharp tip. Individual shaped abrasiveparticles can include any one or more of these features.

According to various embodiments, the bonded abrasive article precursorcan include one or more fillers or grinding aids. Grinding aids can beeffective in abrading stainless steel, exotic metal alloys, titanium,metals slow to oxidize, and so forth. In some instances, a bondedabrasive product including a grinding aid can abrade more stainlesssteel than a corresponding bonded abrasive product which is devoid of agrinding aid. It is believed that one function of a grinding aid is toprevent metal capping by rapidly contaminating the freshly formed metalsurface. Examples of common grinding aids or fillers include sodiumaluminum hexafluoride (e.g., cryolite), sodium chloride, potassiumtetrafluoroborate (KBF₄), iron pyrite, polyvinyl chloride, calciumcarbonate, and polyvinylidene chloride.

The bonded abrasive article precursor can also include conventional(e.g., crushed) abrasive particles as opposed to, on in addition to, anyof the shaped abrasive particles described herein. The conventionalabrasive particles can, for example, have an average diameter rangingfrom about 10 μm to about 5000 μm, about 20 μm to about 200 μm, about 50μm to about 1000 μm, less than, equal to, or greater than about 10 μm,20, 30, 40, 50, 100, 150, 200, 250, 300, 350, 400, 450, 500, 550, 600,650, 700, 750, 800, 850, 900, 950, 1000, 1050, 1100, 1150, 1200, 1250,1300, 1350, 1400, 1450, 1500, 1550, 1650, 1700, 1750, 1800, 1850, 1900,1950, 2000, 2050, 2100, 2150, 2200, 2250, 2300, 2350, 2400, 2450, 2500,2550, 2650, 2700, 2750, 2800, 2850, 2900, 2950, 3000, 3050, 3100, 3150,3200, 3250, 3300, 3350, 3400, 3450, 3500, 3550, 3650, 3700, 3750, 3800,3850, 3900, 3950, 4000, 4050, 4100, 4150, 4200, 4250, 4300, 4350, 4400,4450, 4500, 4550, 4650, 4700, 4750, 4800, 4850, 4900, 4950, or about5000 μm. For example, the conventional abrasive particles can have anabrasives industry-specified nominal grade. Such abrasivesindustry-accepted grading standards include those known as the AmericanNational Standards Institute, Inc. (ANSI) standards, Federation ofEuropean Producers of Abrasive Products (FEPA) standards, and JapaneseIndustrial Standard (HS) standards. Exemplary ANSI grade designations(e.g., specified nominal grades) include: ANSI 12 (1842 μm), ANSI 16(1320 μm), ANSI 20 (905 μm), ANSI 24 (728 μm), ANSI 36 (530 μm), ANSI 40(420 μm), ANSI 50 (351 μm), ANSI 60 (264 μm), ANSI 80 (195 μm), ANSI 100(141 μm), ANSI 120 (116 μm), ANSI 150 (93 μm), ANSI 180 (78 μm), ANSI220 (66 μm), ANSI 240 (53 μm), ANSI 280 (44 μm), ANSI 320 (46 μm), ANSI360 (30 μm), ANSI 400 (24 μm), and ANSI 600 (16 μm). Exemplary FEPAgrade designations include P12 (1746 μm), P16 (1320 μm), P20 (984 μm),P24 (728 μm), P30 (630 μm), P36 (530 μm), P40 (420 μm), P50 (326 μm),P60 (264 μm), P80 (195 μm), P100 (156 μm), P120 (127 μm), P120 (127 μm),P150 (97 μm), P180 (78 μm), P220 (66 μm), P240 (60 μm), P280 (53 μm),P320 (46 μm), P360 (41 μm), P400 (36 μm), P500 (30 μm), P600 (26 μm),and P800 (22 μm). An approximate average particles size of reach gradeis listed in parenthesis following each grade designation.

Shaped abrasive particles 100, 200, 300, 400, 500, or 600 or any crushedabrasive particles further described herein can include any suitablematerial or mixture of materials. For example, shaped abrasive particles100, 200, 300, 400, 500, or 600 can include a material chosen from analpha-alumina, a fused aluminum oxide, a heat-treated aluminum oxide, aceramic aluminum oxide, a sintered aluminum oxide, a silicon carbide, atitanium diboride, a boron carbide, a tungsten carbide, a titaniumcarbide, a diamond, a cubic boron nitride, a garnet, a fusedalumina-zirconia, a sol-gel derived abrasive particle, a cerium oxide, azirconium oxide, a titanium oxide, and combinations thereof. In variousembodiments, shaped abrasive particles 100, 200, 300, 400, 500, or 600and crushed abrasive particles can include the same materials. Infurther embodiments, shaped abrasive particles 100, 200, 300, 400, 500,or 600 and crushed abrasive particles can include different materials.

In addition to the materials already described, at least one magneticmaterial may be included within or coated to shaped abrasive particle100, 200, 300, 400, 500, or 600. Examples of magnetic materials includeiron; cobalt; nickel; various alloys of nickel and iron marketed asPermalloy in various grades; various alloys of iron, nickel and cobaltmarketed as Fernico, Kovar, FerNiCo I, or FerNiCo II; various alloys ofiron, aluminum, nickel, cobalt, and sometimes also copper and/ortitanium marketed as Alnico in various grades; alloys of iron, silicon,and aluminum (about 85:9:6 by weight) marketed as Sendust alloy; Heusleralloys (e.g., Cu₂MnSn); manganese bismuthide (also known as Bismanol);rare earth magnetizable materials such as gadolinium, dysprosium,holmium, europium oxide, alloys of neodymium, iron and boron (e.g.,Nd₂Fe₁₄B), and alloys of samarium and cobalt (e.g., SmCo₅); MnSb;MnOFe₂O₃; Y₃Fe₅O₁₂; CrO₂; MnAs; ferrites such as ferrite, magnetite,zinc ferrite; nickel ferrite; cobalt ferrite, magnesium ferrite, bariumferrite, and strontium ferrite; yttrium iron garnet; and combinations ofthe foregoing. In various embodiments, the magnetizable material is analloy containing 8 to 12 weight percent aluminum, 15 to 26 wt % nickel,5 to 24 wt % cobalt, up to 6 wt % copper, up to 1% titanium, wherein thebalance of material to add up to 100 wt % is iron. In some otherembodiments, a magnetizable coating can be deposited on an abrasiveparticle 100 using a vapor deposition technique such as, for example,physical vapor deposition (PVD) including magnetron sputtering.

Including these magnetizable materials can allow shaped abrasiveparticle 100, 200, 300, 400, 500, or 600 to be responsive to a magneticfield. Any of shaped abrasive particles 100, 200, 300, 400, 500, or 600can include the same material or include different materials.

Furthermore, some shaped abrasive particles 100, 200, 300, 400, 500, or600 can include a polymeric material and can be characterized as softabrasive particles. The low temperature at which the curable resinsdescribed herein are cured at, can allow for inclusion of these softabrasive particles, which may otherwise thermally degrade if exposed tothe temperatures required to cure or mold a bonded abrasive articleincluding a phenolic resin binder, vitrified binder, or metallic binder.The soft shaped abrasive particles described herein can independentlyinclude any suitable material or combination of materials. For example,the soft shaped abrasive particles can include a reaction product of apolymerizable mixture including one or more polymerizable resins, theone or more polymerizable resins such as a hydrocarbyl polymerizableresin. Examples of such resins include those chosen from a phenolicresin, a urea formaldehyde resin, a urethane resin, a melamine resin, anepoxy resin, a bismaleimide resin, a vinyl ether resin, an aminoplastresin (which may include pendant alpha, beta unsaturated carbonylgroups), an acrylate resin, an acrylated isocyanurate resin, anisocyanurate resin, an acrylated urethane resin, an acrylated epoxyresin, an alkyl resin, a polyester resin, a drying oil, or mixturesthereof. The polymerizable mixture can include additional componentssuch as a plasticizer, a catalyst, a cross-linker, a surfactant, amild-abrasive, a pigment, a catalyst and an antibacterial agent.

Where multiple components are present in the polymerizable mixture,those components can account for any suitable weight percentage of themixture. For example, the polymerizable resin or resins may be in arange of from about 35 wt % to about 99.9 wt % of the polymerizablemixture, about 40 wt % to about 95 wt %, or less than, equal to, orgreater than about 35 wt %, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50,51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68,69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86,87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, or about 99.9 wt %.

If present, the cross-linker may be in a range of from about 2 wt % toabout 60 wt % of the polymerizable mixture, from about 5 wt % to about10 wt %, or less than, equal to, or greater than about 2 wt %, 3, 4, 5,6, 7, 8, 9, 10, 11, 12, 13, 14, or about 15 wt %. Examples of suitablecross-linkers include a cross-linker available under the tradedesignation CYMEL 303 LF, of Allnex USA Inc., Alpharetta, Ga., USA; or across-linker available under the trade designation CYMEL 385, of AllnexUSA Inc., Alpharetta, Ga., USA.

If present, the mild-abrasive may be in a range of from about 5 wt % toabout 65 wt % of the polymerizable mixture, about 10 wt % to about 20 wt%, or less than, equal to, or greater than about 5 wt %, 6, 7, 8, 9, 10,11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28,29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46,47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64,or about 65 wt %. Examples of suitable mild-abrasives include amild-abrasive available under the trade designation MINSTRON 353 TALC,of Imerys Talc America, Inc., Three Forks, Mont., USA; a mild-abrasiveavailable under the trade designation USG TERRA ALBA NO. 1 CALCIUMSULFATE, of USG Corporation, Chicago, Ill., USA; Recycled Glass (40-70Grit) available from ESCA Industries, Ltd., Hatfield, Pa., USA, silica,calcite, nepheline, syenite, calcium carbonate, or mixtures thereof.

If present, the plasticizer may be in a range of from about 5 wt % toabout 40 wt % of the polymerizable mixture, about 10 wt % to about 15 wt%, or less than, equal to, or greater than about 5 wt %, 6, 7, 8, 9, 10,11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28,29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, or about 40 wt %. Examplesof suitable plasticizers include acrylic resins or styrene butadieneresins. Examples of acrylic resins include an acrylic resin availableunder the trade designation RHOPLEX GL-618, of DOW Chemical Company,Midland, Mich., USA; an acrylic resin available under the tradedesignation HYCAR 2679, of the Lubrizol Corporation, Wickliffe, Ohio,USA; an acrylic resin available under the trade designation HYCAR 26796,of the Lubrizol Corporation, Wickliffe, Ohio, USA; a polyether polyolavailable under the trade designation ARCOL LG-650, of DOW ChemicalCompany, Midland, Mich., USA; or an acrylic resin available under thetrade designation HYCAR 26315, of the Lubrizol Corporation, Wickliffe,Ohio, USA. An example of a styrene butadiene resin includes a resinavailable under the trade designation ROVENE 5900, of Mallard CreekPolymers, Inc., Charlotte, N.C., USA.

If present, the catalyst may be in a range of from 1 wt % to about 20 wt% of the polymerizable mixture, about 5 wt % to about 10 wt %, or lessthan, equal to, or greater than about 1 wt %, 2, 3, 4, 5, 6, 7, 8, 9,10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or about 20 wt %. Examples ofsuitable catalysts include a solution of aluminum chloride or a solutionof ammonium chloride.

If present, the surfactant can be in a range of from about 0.001 wt % toabout 15 wt % of the polymerizable mixture, about 5 wt % to about 10 wt%, less than, equal to, or greater than about 0.001 wt %, 0.01, 0.5, 1,2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, or about 15 wt %. Examplesof suitable surfactants include a surfactant available under the tradedesignation GEMTEX SC-85-P, of Innospec Performance Chemicals,Salisbury, N.C., USA; a surfactant available under the trade designationDYNOL 604, of Air Products and Chemicals, Inc., Allentown, Pa., USA; asurfactant available under the trade designation ACRYSOL RM-8W, of DOWChemical Company, Midland, Mich., USA; or a surfactant available underthe trade designation XIAMETER AFE 1520, of DOW Chemical Company,Midland, Mich., USA.

If present, the antimicrobial agent may be in a range of from 0.5 wt %to about 20 wt % of the polymerizable mixture, about 10 wt % to about 15wt %, or less than, equal to, or greater than about 0.5 wt %, 1, 2, 3,4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or about 20 wt%. An example of a suitable antimicrobial agent includes zincpyrithione.

If present, the pigment may be in a range of from about 0.1 wt % toabout 10 wt % of the polymerizable mixture, about 3 wt % to about 5 wt%, less than, equal to, or greater than about 0.1 wt %, 0.2, 0.4, 0.6,0.8, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9,9.5, or about 10 wt %. Examples of suitable pigments include a pigmentdispersion available under the trade designation SUNSPERSE BLUE 15, ofSun Chemical Corporation, Parsippany, N.J., USA; a pigment dispersionavailable under the trade designation SUNSPERSE VIOLET 23, of SunChemical Corporation, Parsippany, N.J., USA; a pigment dispersionavailable under the trade designation SUN BLACK, of Sun ChemicalCorporation, Parsippany, N.J., USA; or a pigment dispersion availableunder the trade designation BLUE PIGMENT B2G, of Clariant Ltd.,Charlotte, N.C., USA. The mixture of components can be polymerized bycuring.

Shaped abrasive particle 100, 200, 300, 400, 500, or 600 can be formedin many suitable manners; for example, shaped abrasive particle 100,200, 300, 400, 500, or 600 can be made according to a multi-operationprocess. The process can be carried out using any material or precursordispersion material. Briefly, for embodiments where shaped abrasiveparticles 100, 200, 300, 400, 500, or 600 are monolithic ceramicparticles, the process can include the operations of making either aseeded or non-seeded precursor dispersion that can be converted into acorresponding ceramic (e.g., a boehmite sol-gel that can be converted toalpha alumina); filling one or more mold cavities having the desiredouter shape of shaped abrasive particle 100, 200, 300, 400, 500, or 600with a precursor dispersion; drying the precursor dispersion to formprecursor shaped abrasive particle; removing the precursor shapedabrasive particle 100, 200, 300, 400, 500, or 600 from the moldcavities; calcining the precursor shaped abrasive particle 100, 200,300, 400, 500, or 600 to form calcined, precursor shaped abrasiveparticle 100, 200, 300, 400, 500, or 600; and then sintering thecalcined, precursor shaped abrasive particle 100, 200, 300, 400, 500, or600 to form shaped abrasive particle 100, 200, 300, 400, 500, or 600.The process will now be described in greater detail in the context ofalpha-alumina-containing shaped abrasive particle 100, 200, 300, 400,500, or 600. In other embodiments, the mold cavities may be filled witha melamine to form melamine shaped abrasive particles.

The process can include the operation of providing either a seeded ornon-seeded dispersion of a precursor that can be converted into ceramic.In examples where the precursor is seeded, the precursor can be seededwith an oxide of an iron (e.g., FeO). The precursor dispersion caninclude a liquid that is a volatile component. In one example, thevolatile component is water. The dispersion can include a sufficientamount of liquid for the viscosity of the dispersion to be sufficientlylow to allow filling mold cavities and replicating the mold surfaces,but not so much liquid as to cause subsequent removal of the liquid fromthe mold cavity to be prohibitively expensive. In one example, theprecursor dispersion includes from 2 percent to 90 percent by weight ofthe particles that can be converted into ceramic, such as particles ofaluminum oxide monohydrate (boehmite), and at least 10 percent byweight, or from 50 percent to 70 percent, or 50 percent to 60 percent,by weight, of the volatile component such as water. Conversely, theprecursor dispersion in various embodiments contains from 30 percent to50 percent, or 40 percent to 50 percent solids by weight.

Examples of suitable precursor dispersions include zirconium oxide sols,vanadium oxide sols, cerium oxide sols, aluminum oxide sols, andcombinations thereof. Suitable aluminum oxide dispersions include, forexample, boehmite dispersions and other aluminum oxide hydratesdispersions. Boehmite can be prepared by known techniques or can beobtained commercially. Examples of commercially available boehmiteinclude products having the trade designations “DISPERAL” and “DISPAL”,both available from Sasol North America, Inc., or “HIQ-40” availablefrom BASF Corporation. These aluminum oxide monohydrates are relativelypure; that is, they include relatively little, if any, hydrate phasesother than monohydrates, and have a high surface area.

The physical properties of the resulting shaped abrasive particle 100,200, 300, 400, 500, or 600 can generally depend upon the type ofmaterial used in the precursor dispersion. As used herein, a “gel” is athree-dimensional network of solids dispersed in a liquid.

The precursor dispersion can contain a modifying additive or precursorof a modifying additive. The modifying additive can function to enhancesome desirable property of the abrasive particles or increase theeffectiveness of the subsequent sintering step. Modifying additives orprecursors of modifying additives can be in the form of soluble salts,such as water-soluble salts. They can include a metal-containingcompound and can be a precursor of an oxide of magnesium, zinc, iron,silicon, cobalt, nickel, zirconium, hafnium, chromium, yttrium,praseodymium, samarium, ytterbium, neodymium, lanthanum, gadolinium,cerium, dysprosium, erbium, titanium, and mixtures thereof. Theparticular concentrations of these additives that can be present in theprecursor dispersion can be varied.

The introduction of a modifying additive or precursor of a modifyingadditive can cause the precursor dispersion to gel. The precursordispersion can also be induced to gel by application of heat over aperiod of time to reduce the liquid content in the dispersion throughevaporation. The precursor dispersion can also contain a nucleatingagent. Nucleating agents suitable for this disclosure can include fineparticles of alpha alumina, alpha ferric oxide or its precursor,titanium oxides and titanates, chrome oxides, or any other material thatwill nucleate the transformation. The amount of nucleating agent, ifused, should be sufficient to effect the transformation of alphaalumina.

A peptizing agent can be added to the precursor dispersion to produce amore stable hydrosol or colloidal precursor dispersion. Suitablepeptizing agents are monoprotic acids or acid compounds such as aceticacid, hydrochloric acid, formic acid, and nitric acid. Multiprotic acidscan also be used, but they can rapidly gel the precursor dispersion,making it difficult to handle or to introduce additional components.Some commercial sources of boehmite contain an acid titer (such asabsorbed formic or nitric acid) that will assist in forming a stableprecursor dispersion.

The precursor dispersion can be formed by any suitable means; forexample, in the case of a sol-gel alumina precursor, it can be formed bysimply mixing aluminum oxide monohydrate with water containing apeptizing agent or by forming an aluminum oxide monohydrate slurry towhich the peptizing agent is added.

Defoamers or other suitable chemicals can be added to reduce thetendency to form bubbles or entrain air while mixing. Additionalchemicals such as wetting agents, alcohols, or coupling agents can beadded if desired.

A further operation can include providing a mold having at least onemold cavity, or a plurality of cavities formed in at least one majorsurface of the mold. In some examples, the mold is formed as aproduction tool, which can be, for example, a belt, a sheet, acontinuous web, a coating roll such as a rotogravure roll, a sleevemounted on a coating roll, or a die. In one example, the production toolcan include polymeric material. Examples of suitable polymeric materialsinclude thermoplastics such as polyesters, polycarbonates, poly(ethersulfone), poly(methyl methacrylate), polyurethanes, polyvinylchloride,polyolefin, polystyrene, polypropylene, polyethylene or combinationsthereof, or thermosetting materials. In one example, the entire tool ismade from a polymeric or thermoplastic material. In another example, thesurfaces of the tool in contact with the precursor dispersion while theprecursor dispersion is drying, such as the surfaces of the plurality ofcavities, include polymeric or thermoplastic materials, and otherportions of the tool can be made from other materials. A suitablepolymeric coating can be applied to a metal tool to change its surfacetension properties, by way of example.

A polymeric or thermoplastic production tool can be replicated off ametal master tool. The master tool can have the inverse pattern of thatdesired for the production tool. The master tool can be made in the samemanner as the production tool. In one example, the master tool is madeof metal (e.g., nickel) and is diamond-turned. In one example, themaster tool is at least partially formed using stereolithography. Thepolymeric sheet material can be heated along with the master tool suchthat the polymeric material is embossed with the master tool pattern bypressing the two together. A polymeric or thermoplastic material canalso be extruded or cast onto the master tool and then pressed. Thethermoplastic material is cooled to solidify and produce the productiontool. If a thermoplastic production tool is utilized, then care shouldbe taken not to generate excessive heat that can distort thethermoplastic production tool, limiting its life.

Access to cavities can be from an opening in the top surface or bottomsurface of the mold. In some examples, the cavities can extend for theentire thickness of the mold. Alternatively, the cavities can extendonly for a portion of the thickness of the mold. In one example, the topsurface is substantially parallel to the bottom surface of the mold withthe cavities having a substantially uniform depth. At least one side ofthe mold, the side in which the cavities are formed, can remain exposedto the surrounding atmosphere during the step in which the volatilecomponent is removed.

The cavities have a specified three-dimensional shape to make shapedabrasive particle 100. The depth dimension is equal to the perpendiculardistance from the top surface to the lowermost point on the bottomsurface. The depth of a given cavity can be uniform or can vary alongits length and/or width. The cavities of a given mold can be of the sameshape or of different shapes.

A further operation involves filling the cavities in the mold with theprecursor dispersion (e.g., by a conventional technique). In someexamples, a knife roll coater or vacuum slot die coater can be used. Amold release agent can be used to aid in removing the particles from themold if desired. Examples of mold release agents include oils such aspeanut oil or mineral oil, fish oil, silicones, polytetrafluoroethylene,zinc stearate, and graphite. In general, a mold release agent such aspeanut oil, in a liquid, such as water or alcohol, is applied to thesurfaces of the production tool in contact with the precursor dispersionsuch that from about 0.1 mg/in² (0.6 mg/cm²) to about 3.0 mg/in² (20mg/cm²), or from about 0.1 mg/in² (0.6 mg/cm²) to about 5.0 mg/in² (30mg/cm²), of the mold release agent is present per unit area of the moldwhen a mold release is desired. In various embodiments, the top surfaceof the mold is coated with the precursor dispersion. The precursordispersion can be pumped onto the top surface.

In a further operation, a scraper or leveler bar can be used to forcethe precursor dispersion fully into the cavity of the mold. Theremaining portion of the precursor dispersion that does not enter thecavity can be removed from the top surface of the mold and recycled. Insome examples, a small portion of the precursor dispersion can remain onthe top surface, and in other examples the top surface is substantiallyfree of the dispersion. The pressure applied by the scraper or levelerbar can be less than 100 psi (0.6 MPa), or less than 50 psi (0.3 MPa),or even less than 10 psi (60 kPa). In some examples, no exposed surfaceof the precursor dispersion extends substantially beyond the topsurface.

In those examples where it is desired to have the exposed surfaces ofthe cavities result in planar faces of the shaped abrasive particles, itcan be desirable to overfill the cavities (e.g., using a micronozzlearray) and slowly dry the precursor dispersion.

A further operation involves removing the volatile component to dry thedispersion. The volatile component can be removed by fast evaporationrates. In some examples, removal of the volatile component byevaporation occurs at temperatures above the boiling point of thevolatile component. An upper limit to the drying temperature oftendepends on the material the mold is made from. For polypropylene tool,the temperature should be less than the melting point of the plastic. Inone example, for a water dispersion of from about 40 to 50 percentsolids and a polypropylene mold, the drying temperatures can be fromabout 90° C. to about 165° C., or from about 105° C. to about 150° C.,or from about 105° C. to about 120° C. Higher temperatures can lead toimproved production speeds but can also lead to degradation of thepolypropylene tool, limiting its useful life as a mold.

During drying, the precursor dispersion shrinks, often causingretraction from the cavity walls. For example, if the cavities haveplanar walls, then the resulting shaped abrasive particle 100 can tendto have at least three concave major sides. It is presently discoveredthat by making the cavity walls concave (whereby the cavity volume isincreased) it is possible to obtain shaped abrasive particle 100, 200,300, 400, 500, or 600 that have at least three substantially planarmajor sides. The degree of concavity generally depends on the solidscontent of the precursor dispersion.

A further operation involves removing resultant precursor shapedabrasive particle 100, 200, 300, 400, 500, or 600 from the moldcavities. The precursor shaped abrasive particle 100, 200, 300, 400,500, or 600 can be removed from the cavities by using the followingprocesses alone or in combination on the mold: gravity, vibration,ultrasonic vibration, vacuum, or pressurized air to remove the particlesfrom the mold cavities.

The precursor shaped abrasive particle 100, 200, 300, 400, 500, or 600can be further dried outside of the mold. If the precursor dispersion isdried to the desired level in the mold, this additional drying step isnot necessary. However, in some instances it can be economical to employthis additional drying step to minimize the time that the precursordispersion resides in the mold. The precursor shaped abrasive particle100, 200, 300, 400, 500, or 600 will be dried from 10 to 480 minutes, orfrom 120 to 400 minutes, at a temperature from 50° C. to 160° C., or120° C. to 150° C.

A further operation involves calcining the precursor shaped abrasiveparticle 100, 200, 300, 400, 500, or 600. During calcining, essentiallyall the volatile material is removed, and the various components thatwere present in the precursor dispersion are transformed into metaloxides. The precursor shaped abrasive particle 100, 200, 300, 400, 500,or 600 is generally heated to a temperature from 400° C. to 800° C. andmaintained within this temperature range until the free water and over90 percent by weight of any bound volatile material are removed. In anoptional step, it can be desirable to introduce the modifying additiveby an impregnation process. A water-soluble salt can be introduced byimpregnation into the pores of the calcined, precursor shaped abrasiveparticle 100, 200, 300, 400, 500, or 600. Then the precursor shapedabrasive particle 100, 200, 300, 400, 500, or 600 are pre-fired again.

A further operation can involve sintering the calcined, precursor shapedabrasive particle 100, 200, 300, 400, 500, or 600 to form particles 100,200, 300, 400, 500, or 600. In some examples where the precursorincludes rare earth metals, however, sintering may not be necessary.Prior to sintering, the calcined, precursor shaped abrasive particle100, 200, 300, 400, 500, or 600 are not completely densified and thuslack the desired hardness to be used as shaped abrasive particle 100,200, 300, 400, 500, or 600. Sintering takes place by heating thecalcined, precursor shaped abrasive particle 100, 200, 300, 400, 500, or600 to a temperature of from 1000° C. to 1650° C. The length of time forwhich the calcined, precursor shaped abrasive particle 100, 200, 300,400, 500, or 600 can be exposed to the sintering temperature to achievethis level of conversion depends upon various factors, but from fiveseconds to 48 hours is possible.

In another embodiment, the duration of the sintering step ranges fromone minute to 90 minutes. After sintering, shaped abrasive particle 100,200, 300, 400, 500, or 600 can have a Vickers hardness of 10 GPa(gigaPascals), 16 GPa, 18 GPa, 20 GPa, or greater. Additional operationscan be used to modify the described process, such as, for example,rapidly heating the material from the calcining temperature to thesintering temperature and centrifuging the precursor dispersion toremove sludge and/or waste. Moreover, the process can be modified bycombining two or more of the process steps if desired.

The bonded abrasive article precursor can be cured to form a bondedabrasive article. FIGS. 7 and 8 show an embodiment of bonded abrasivearticle 700. Specifically, FIG. 7 is a perspective view of bondedabrasive article 700 and FIG. 8 is a sectional view of bonded abrasivearticle 700 taken along line 2-2 of FIG. 7. FIGS. 7 and 8 show many ofthe same features and are discussed concurrently. As depicted, bondedabrasive article 700 is a depressed center grinding wheel. In otherembodiments, the bonded abrasive article can be a cut-off wheel, cuttingwheel, a cut-and-grind wheel, a depressed center cut-off wheel, a reelgrinding wheel, a mounted point, a tool grinding wheel, a roll grindingwheel, a hot-pressed grinding wheel, a face grinding wheel, a railgrinding wheel, a grinding cone, a grinding plug, a cup grinding wheel,a gear grinding wheel, a centerless grinding wheel, a cylindricalgrinding wheel, an inner diameter grinding wheel, an outer diametergrinding wheel, or a double disk grinding wheel. The dimensions of thewheel can be any suitable size; for example, the diameter can range from2 mm to about 2000 mm, about 100 mm to about 500 mm, less than, equalto, or greater than about 2 mm, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100,110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240,250, 260, 270, 280, 290, 300, 310, 320, 330, 340, 350, 360, 370, 380,390, 400, 410, 420, 430, 440, 450, 460, 470, 480, 490, 500, 510, 520,530, 540, 550, 560, 570, 580, 590, 600, 610, 620, 630, 640, 650, 660,670, 680, 690, 700, 710, 720, 730, 740, 750, 760, 770, 780, 790, 800,810, 820, 830, 840, 850, 860, 870, 880, 890, 900, 910, 920, 930, 940,950, 960, 970, 980, 990, 1000, 1110, 1120, 1130, 1140, 1150, 1160, 1170,1180, 1190, 1200, 1210, 1220, 1230, 1240, 1250, 1260, 1270, 1280, 1290,1300, 1310, 1320, 1330, 1340, 1350, 1360, 1370, 1380, 1390, 1400, 1410,1420, 1430, 1440, 1450, 1460, 1470, 1480, 1490, 1500, 1510, 1520, 1530,1540, 1550, 1560, 1570, 1580, 1590, 1600, 1610, 1620, 1630, 1640, 1650,1660, 1670, 1680, 1690, 1700, 1710, 1720, 1730, 1740, 1750, 1760, 1770,1780, 1790, 1800, 1810, 1820, 1830, 1840, 1850, 1860, 1870, 1880, 1890,1900, 1910, 1920, 1930, 1940, 1950, 1960, 1970, 1980, 1990, or about2000 mm.

Bonded abrasive article 700 includes first major surface 702 and secondmajor surface 702. First major surface 702 and second major surface 702have a substantially circular profile. Central aperture 716 extendsbetween first major surface 702 and second major surface 702 and can beused, for example, for attachment to a power-driven tool. In examples ofother abrasive articles, central aperture 716 can be designed to onlyextend partially between first and second major surfaces 702 and 704.

As shown, shaped abrasive particles 100 are attached to reinforcingcomponent 705 and arranged in layers. Although shaped abrasive particles100 are shown, it is possible for bonded abrasive article 700 to includeany of the other shaped or conventional abrasive particles describedherein. Additionally, although shaped abrasive particles 100 are shownattached to reinforcing component 705, in various embodiments, bondedabrasive article 700, may be free of any reinforcing component 705.Additionally, the cured composition may be degraded during curing,leaving only shaped abrasive particles 100. Where present, reinforcinglayer 705 can include a polymeric film, a metal foil, a woven fabric, aknitted fabric, paper, vulcanized fiber, a staple fiber, a continuousfiber, a nonwoven, a foam, a screen, a laminate, and combinationsthereof.

As shown in FIGS. 7 and 8, bonded abrasive article 700 includes firstlayer of abrasive particles 712 and second layer of abrasive particles714. First layer of abrasive particles 712 and second layer of abrasiveparticles 714 are spaced apart from one another with the binder locatedtherebetween. The binder is the cured epoxy, polyurethane, orpolyacrylate network. Although two layers of abrasive particles 100 areshown, bonded abrasive article 700 can include additional layers ofabrasive particles. For example, bonded abrasive article 700 can includea third layer of abrasive particles adjacent to at least one of first orsecond layers of abrasive particles 712 and 714.

As shown, at least a majority of the abrasive particles 100 are notrandomly distributed within first and second layers 712 and 714. Rather,abrasive particles 100 are distributed according to a predeterminedpattern. For example, FIG. 8 shows a pattern where adjacent abrasiveparticles 100 of first layer of abrasive particles 712 are directlyaligned with each other in rows extending from central aperture 716 tothe perimeter of bonded abrasive article 700. The adjacent abrasiveparticles are also directly aligned in concentric circles.

Abrasive particles 100 in each layer do not have to be the same abrasiveparticle. For example, first layer of abrasive particles 712 can includeat least a first plurality of abrasive particles 100 and a secondplurality of abrasive particles 100. The first plurality of abrasiveparticles 100 and the second plurality of abrasive particles 100 canindividually range from about from about 10 wt % to about 100 wt % ofthe first layer of abrasive particles 712, or from about 20 wt % toabout 90 wt %, or from about 30 wt % to about 80 wt %, or from about 40wt % to about 60 wt %, or less than about, equal to about, or greaterthan about 15 wt %, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80,85, 90, or 95 wt %.

In still further embodiments, bonded abrasive article 700 may onlyinclude first layer of abrasive particles 712, but instead of being aplanar layer, layer 712 can conform to a helical shape centered about az-axis and extending from first major surface 702 to second surface 704.

As shown in FIGS. 7 and 8, each of the plurality of shaped abrasiveparticles 100 can have a specified z-direction rotational orientationabout a z-axis passing through individual shaped abrasive particles 100and through reinforcing component 705 at a 90 degree angle toreinforcing component 705. Shaped abrasive particles 100 are orientatedwith a surface feature, such as a substantially planar surface ofparticle 100, rotated into a specified angular position about thez-axis. The specified z-direction rotational orientation occurs morefrequently than would occur by a random z-directional rotationalorientation of the surface feature due to electrostatic coating or dropcoating of shaped abrasive particles 100, 200, 300, 400, 500, or 600when forming bonded abrasive article precursor. As such, by controllingthe z-direction rotational orientation of a significantly large numberof shaped abrasive particles 100, the cut rate, finish, or both of aresulting bonded abrasive article to which bonded abrasive articleprecursor is applied can be varied from those manufactured using anelectrostatic coating method. In various embodiments, at least 50, 51,55, 60, 65, 70, 75, 80, 85, 90, 95, or 99 percent of shaped abrasiveparticles 100 can have a specified z-direction rotational orientationwhich does not occur randomly and which can be substantially the samefor all of the aligned particles. In other embodiments, about 50 percentof shaped abrasive particles 100 can be aligned in a first direction andabout 50 percent of shaped abrasive particles 100 can be aligned in asecond direction. In one embodiment, the first direction issubstantially orthogonal to the second direction.

Abrasive particles 100 of the first and second pluralities of particlescan differ in respect to the shape, size, or type of abrasive particle100. For example, the first plurality of abrasive particles can beshaped abrasive particles whereas the second plurality of abrasiveparticles can be crushed abrasive particles. In other embodiments, thefirst and second pluralities of abrasive particles 100 can be a sametype of abrasive particle 100 (e.g., a shaped abrasive particle) but maydiffer in size. In further embodiments, the first and second pluralitiesof particles may be different types of abrasive particles but may havesubstantially the same size. The second, third, and any additionallayers of abrasive particles can include pluralities of abrasiveparticles that are similar to those of the first layer of abrasiveparticles.

According to various embodiments, about 80 wt % to about 100 wt % of thereactants (e.g., the curable resins) of the bonded abrasive articleprecursor can be polymerized, about 99.9 wt % to about 95 wt %, lessthan, equal to, or greater than about 80 wt %, 81, 82, 83, 84, 85, 86,87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, or about 100 wt %.The extent to which the reactants are polymerized can be measured usingdifferential scanning calorimetry to determine the % cure. According tovarious embodiments, % cure=[1−(ΔH/ΔH₀)]*100, where ΔH₀ is the cureexotherm of the uncured reactants. The % cure can be in a range of fromabout 80% to about 100%, about 90% to about 95%, less than, equal to, orgreater than about 80%, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92,93, 94, 95, 96, 97, 98, 99, or about 100%. In various embodiments, thepolymerization reaction is not a condensation reaction and water,therefore, accounts for less than about 2 wt %, 1.5, 1, or 0.5 wt % ofbonded abrasive article 700.

Bonded abrasive article 700 can be formed according to many suitablemethods. For example, the curable composition can be placed in a moldhaving a shape corresponding to the final shape of the desired bondedabrasive article. The curable composition can then be cured directly byexposing the curable composition to an appropriate temperature for a setamount of time. However, this may not make it possible to form a bondedabrasive article where abrasive particles 100, for example, areprecisely arranged. If a precise arrangement is desired, an apparatussuch as apparatus 800 may be used.

FIGS. 8 and 9 are discussed concurrently. As shown, apparatus 800includes housing 802. Housing 802 is formed from housing first majorsurface 804 and opposed housing second major surface 806. Housing firstmajor surface 804 and housing second major surface 806 are connected byhousing peripheral surface 808.

Apparatus first major surface 804 has a substantially planar profile andincludes a plurality of holes 810 extending therethrough. Each hole 810is adapted to receive an abrasive particle. At least some of holes 810are further arranged on apparatus first major surface 804 in a pattern.The pattern can correspond to, for example, the predetermined pattern ofthe abrasive particles of bonded abrasive article precursor. In someexamples, holes 810 can be randomly arranged. In still other examples,at least some of holes 810 can be arranged in a pattern, whereas otherholes are randomly arranged.

The type of abrasive particle that hole 810 receives is a function ofthe size (e.g., width) and shape of each hole 810. Each hole 810 canreceive particles that have a width smaller than the width of hole 810.This provides a first screening feature to help ensure that only desiredabrasive particles are received by holes 810. A second screening featureis the shape of hole 810.

Holes 810 can have any suitable polygonal shape. For example, thepolygonal shape can be substantially triangular, circular, rectangular,pentagonal, substantially hexagonal, and so forth. These shapes can beadapted to receive specific shaped abrasive particles. For example, ifhole 810 is triangularly shaped, it may be best suited to receive atriangularly shaped abrasive particle. Due to the triangular shape, asquare shaped abrasive particle will not fit in hole 810 (provided thatthe particle has a larger width than the hole). Thus, the shape of hole810 in combination with the width can control the type of abrasiveparticle that is received.

In some examples, each of holes 810 can be in the shape of anequilateral triangular hole. A length of each side can range from about0.5 mm to about 3 mm, or about 1 mm to about 1.5 mm, or less than about,equal to about, or greater than about 1 mm, 1.5 mm, 2 mm, or about 2.5mm. An angle of a sidewall of each hole 810 may range from about 80degrees to about 105 degrees relative to the bottom of each hole, orabout 95 degrees to about 100 degrees, or less than about, equal toabout, or greater than about 85 degrees, 90, 95, or 100 degrees. Thedepth of each hole may range from about 0.10 mm to about 0.50 mm, orabout 0.20 mm to about 0.30 mm or less than about, equal to about, orgreater than about 0.15 mm, 0.20, 0.25, 0.30, 0.35, 0.40, or 0.45 mm.

In addition to having regular shaped holes 810, apparatus 800 can haveirregular shaped holes. That is, the shape of holes 810 can be designedto substantially match the shape of crushed abrasive particles. Whilegreat variety in the dimensions of holes 810 is possible, each hole canalso be designed to have substantially the same size. This configurationmay be desirable for applications in which each abrasive particle hasthe same size.

Holes 810 can be further shaped to have a smaller width on one end ofhole 810 than on the other end. That is, the width of hole 810 atapparatus first major surface 804 can be wider than that of the internalend of hole 810. For example, the width of hole 810 at the first end canrange from about 1.1 to about 4 times larger than the width of the holeat the second end, or about 2 to about 3 times larger, or less thanabout, equal to, or greater than about 1.2, 1.3, 1.4, 1.5, 1.6, 1.7,1.8, 1.9, 2, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3, 3.1, 3.2,3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7,4.8, or 4.9 times larger than the width of hole 810 at the second end.This way the abrasive particle will not pass completely through hole 804and into housing 802. The interior of the holes 810 can also be sloped.This can allow for a specific orientation of shaped abrasive particleswithin hole 810. For example, some abrasive particles may have slopedsidewalls. The interior of holes 810 may in turn be sloped to match thesidewalls of the abrasive particles.

In some examples of apparatus 800, apparatus first major surface 804 canbe releasably secured to housing 802. This can allow the apparatus tohave interchangeable apparatus first surfaces. Each apparatus firstsurface can have differently sized holes or patterns of holes 810. Thus,apparatus 800 can be very versatile in terms of the types of abrasiveparticles that it may receive as well as the patterns it can create.

Apparatus 800 can releasably secure the abrasive particles in any numberof sufficient ways. For example, as shown, housing 802 includes inlet812 located on opposed housing second major surface 806. Inlet 812 canbe adapted to be connected to a vacuum generation system. In operation,a low pressure (e.g., vacuum-like) environment can be created withinhousing 802. Thus, any abrasive particles disposed within the holes 810are retained therein by suction. To release the abrasive particles, thevacuum generation system is turned off, thus resulting in a loss ofsuction. Alternatively, a magnet can be disposed within housing 802 thatcan be selectively engaged or disengaged. If the abrasive particles havemetal in or on them, respectively, then they may be attracted to themagnet and drawn to the holes.

As stated herein bonded abrasive articles 700, according to the presentdisclosure, can be made according to any suitable method. One methodincludes retaining a first plurality of abrasive particles within afirst portion of the plurality of holes of the apparatus describedherein. The apparatus can be positioned within a mold and a plurality ofabrasive particles can be released in the mold and optionally contactingwith reinforcing component 705. Components of the curable compositionsuch as the curable resins and the curative components are thendeposited to form the curable composition. The mold can then be heated,if necessary to begin or increase the rate of curing of the curablecomposition to form boned abrasive article.

If multiple layers of abrasive particles are desired, then multiplelayers of abrasive particles can be deposited in the curable compositionbefore curing. Furthermore, prior to curing, if any of the shapedabrasive particles are responsive to a magnetic field, the orientationof the shaped abrasive particles can be controlled or tuned by exposingthem to a magnetic field and rotating them with the magnetic field.

In various embodiments, bonded abrasive article 700 may act as atransfer tool to form a bonded abrasive article comprising a resinous,vitrified, or metallic binder. For example, bonded abrasive article 700,having shaped abrasive particles 100 arranged according to apredetermined pattern may be placed in a mold and a polymeric resinbinder in the mold and cured to form a resin bonded, vitrified, ormetallic bonded abrasive article. During curing the temperature may behigh enough to thermally degrade the cured network or bonded abrasivearticle 700, leaving shaped abrasive particles 100 arranged according toa predetermined pattern in the phenolic resin bond, vitrified binder, ormetallic binder system. This can be a helpful way to form bondedabrasive articles having shaped abrasive particles arranged according toa predetermined pattern.

According to further embodiments a bonded abrasive article can be formedthat includes alternating layers of materials. For example, a firstlayer can include an epoxy resin whereas a second layer can include aphenolic resin. As another example the first layer and second layer maydiffer by the type of abrasive article that is included in each layer.In a multi-layer construction, the bonded abrasive article may include 2layers, 4 layers, 6 layers, or any plural number of layers.

Useful phenolic resins include novolac and resole phenolic resins.Novolac phenolic resins are characterized by being acid-catalyzed and ashaving a ratio of formaldehyde to phenol of less than one, for example,between 0.5:1 and 0.8:1. Resole phenolic resins are characterized bybeing base catalyzed and having a ratio of formaldehyde to phenol ofgreater than or equal to one, for example from 1:1 to 3:1. Novolac andresole phenolic resins may be chemically modified (e.g., by reactionwith epoxy compounds), or they may be unmodified. Exemplary acidiccatalysts suitable for curing phenolic resins include sulfuric,hydrochloric, phosphoric, oxalic, and p-toluenesulfonic acids. Alkalinecatalysts suitable for curing phenolic resins include sodium hydroxide,barium hydroxide, potassium hydroxide, calcium hydroxide, organicamines, or sodium carbonate.

Phenolic resins can be available from commercial sources. Examples ofcommercially available novolac resins include DUREZ 1364, a two-step,powdered phenolic resin (marketed by Durez Corporation, Addison, Tex.,under the trade designation VARCUM (e.g., 29302), or DURITE RESINAD-5534 (marketed by Hexion, Inc., Louisville, Ky.). Examples ofcommercially available resole phenolic resins useful in practice of thepresent disclosure include those marketed by Durez Corporation under thetrade designation VARCUM (e.g., 29217, 29306, 29318, 29338, 29353);those marketed by Ashland Chemical Co., Bartow, Fla. under the tradedesignation AEROFENE (e.g., AEROFENE 295); and those marketed by KangnamChemical Company Ltd., Seoul, South Korea under the trade designation“PHENOLITE” (e.g., PHENOLITE TD-2207).

With regards to vitrified binding materials, vitreous bonding materials,which exhibit an amorphous structure and are hard, are well known in theart. In some cases, the vitreous bonding material includes crystallinephases. Examples of metal oxides that are used to form vitreous bondingmaterials include: silica, silicates, alumina, soda, calcia, potassia,titania, iron oxide, zinc oxide, lithium oxide, magnesia, boria,aluminum silicate, borosilicate glass, lithium aluminum silicate,combinations thereof, and the like. Vitreous bonding materials can beformed from a composition comprising from 10 to 100% glass frit,although more typically the composition comprises 20% to 80% glass frit,or 30% to 70% glass frit. The remaining portion of the vitreous bondingmaterial can be a non-frit material. Alternatively, the vitreous bondmay be derived from a non-frit containing composition. Vitreous bondingmaterials are typically matured at a temperature(s) in the range fromabout 700° C. to about 1500° C., usually in the range from about 800° C.to about 1300° C., sometimes in the range from about 900° C. to about1200° C., or even in the range from about 950° C. to about 1100° C. Theactual temperature at which the bond is matured depends, for example, onthe particular bond chemistry. Preferred vitrified bonding materials mayinclude those comprising silica, alumina (preferably, at least 10percent by weight alumina), and boria (preferably, at least 10 percentby weight boria). In most cases the vitrified bonding materials furthercomprise alkali metal oxide(s) (e.g., Na₂O and K₂O) (in some cases atleast 10 percent by weight alkali metal oxide(s)).

EXAMPLES

Various embodiments of the present disclosure can be better understoodby reference to the following Examples which are offered by way ofillustration. The present disclosure is not limited to the Examplesgiven herein.

Materials Abbreviation Material PSG Precisely-shaped alpha aluminaabrasive particles prepared according to the disclosure of U.S. Pat. No.US 2015/0267097 Al (Rosenflanz et al.) by molding a slurry comprisingnon-colloidal solid particles and a liquid vehicle in equilateraltriangular polypropylene mold cavities. Triangle edge length was ~1.3 mmwith a thickness of ~0.3 mm. 36 SiC A 36-grit abrasive particleavailable from Washington Mills, North Grafton, MA, under the tradedesignation 15C-36 46 AO A 46-grit fused aluminum oxide available fromImerys, Bahrain, under the trade designation Alodur FRSCC-46 400 AO A400-grit fused aluminum oxide available from Imerys, Bahrain, under thetrade designation Alodur ZWSK F400 WA1 A liquid epoxy novolac resinavailable from Huntsman, Houston TX, available under the tradedesignation Araldite EPN-1179 WA2 A solid epoxy cresol novolac availablefrom Huntsman, Houston TX, under the trade designation Araldite ECN-1273CAT An antimony hexafluoride-based catalyst available from KingIndustries Norwalk, CT, under the trade designation K-PURE CXC-1612 PAFPotassium Aluminum Fluoride obtained from Washington Mills under thetrade name PAF Phenolic A phenolic resin powder available from ResinPowder Hexion, Houston, TX under the trade designation Bakelite 0224SPFurfural 2-furaldehyde available from Aldrich, St. Louis, MO CarbonBlack Luvomaxx LB/S

Bonded abrasive articles of Example 1, Example 2, and ComparativeExample 1 were formed to have an outer diameter (OD) of 125 mm, an innerdiameter (ID) of 22.2 mm, and a thickness of 1.8 mm. Materials andmethods for forming Example 1, Example 2, Example 3, and ComparativeExample 1 are described below.

Example 1

Table 1 lists the materials and amounts used in for Example 1. PSG, 36SiC, and 46 AO were mixed with WA2 for 7 minutes in a Kitchen Aid Mixer.Separately, Solid Epoxy was ground into microparticles using a coffeegrinder. Then WA1 and CAT were added to the PSG, 36 SiC, and 46 AO andmixed for 7 minutes in a Kitchen Aid mixer (Professional 5 SeriesMixer). The mix was first screened in an oven at 130° C. and was foundto cure into a solid block within less than 5 minutes.

40 g of the cured material was deposited into a mold conforming to thedimensions of the final bonded abrasive article. The mold was closedwith a force of 10 tons applied at a temperature of 150° C. for 10minutes. After heating and cooling back to near ambient temperature, thematerial was a consolidated solid indicating cure of the epoxy novolacresin. Differential scanning calorimetry (Table 5) confirmed that theresidual cure exotherm was negligible.

TABLE 1 Components of the bonded abrasive article precursor and articleof Example 1 Material Amount (g) Wt % PSG 357.1 17.9 36 SiC 581.6 29.146 AO 723.4 36.2 WA2 297.1 14.9 WA1 40.9 2.0 CAT 6.76 0.34

Example 2

A powdered pre-mix (Table 2) was first mixed in a food processor for 5minutes. Then WA1 was mixed into PSG and 46 AO for 7 minutes in aKitchen Aid mixer, followed by addition of the powdered premix and aninitial 7-minute mixing step in the Kitchen Aid mixer. All componentswere mixed in the proportions shown in Table 3. The mix was firstscreened in an oven at 130° C. and was found to cure into a solid blockwithin less than 5 minutes.

40 g of the cured material was deposited into a mold conforming to thedimensions of the final bonded abrasive article. The mold was closedwith a force of 10 tons applied at a temperature of 150° C. for 10minutes. After heating and cooling back to near ambient temperature, thematerial was a consolidated solid indicating cure of the epoxy novolacresin. Differential scanning calorimetry (Table 5) confirmed that theresidual cure exotherm was negligible.

TABLE 2 Powdered pre-mix for the bonded abrasive article precursor ofExample 2 Material Amount (g) Wt % WA2 149.2 37.9 PAF 205.4 52.1 400 AO32.3 8.2 Carbon Black 3 0.8 CAT 4 1

TABLE 3 Components of the bonded abrasive article precursor and articleof Example 2 Material Amount (g) Wt % PSG 206 20.80 46 AO 433 43.60 WA128 2.80 Powdered pre-mix 325 32.80

Example 3

A layered abrasive article was formed by taking material from Example 1and Comparative Example 1 and stacking each material for form sixalternative layers. The total thickness was 11 mm and the constructionwas cured for 10 minutes at 150° C., followed by a post-cure of 25 hoursat 190° C. A total of 6 layers were deposited, and the final wheelthickness was 10 mm.

Comparative Example 1

Table 4 lists the materials and amounts used in for ComparativeExample 1. PSG, 36 SiC, and 46 AO were mixed with Phenolic Resin Powderand Furfural for 7 minutes in a Kitchen Aid Mixer.

40 g of the material was deposited into a mold conforming to thedimensions of the final bonded abrasive article. The mold was closedwith a force of 10 tons applied at a temperature of 150° C. for 10minutes. After heating and cooling back to near ambient temperature, thematerial was a soft solid. This soft solid material was analyzed usingdifferential scanning calorimetry (Table 5). The results of thedifferential scanning calorimetry analysis for comparative example 1with the two temperature setpoints are found in Table 5. The resultsshowed that an amount of phenolic/furfural cure has occurred in CE1after 10 minutes at 150° C., but the full cure of the phenolicresin—which typically takes place at 190° C. was not complete.

TABLE 4 Components of the bonded abrasive article precursor and articleof Comparative Example 1 Material Amount (g) Wt % PSG 357 17.9 36 SiC582 29.1 46 AO 723 36.2 Phenolic Resin Powder 317 21 Furfural 21 1

Differential Scanning Calorimetry

A Q2000 differential scanning calorimetry machine (TA Instruments) wasused to measure the exotherm of the bonded abrasive article of Example1, Example 2, and Comparative Example 1 before curing and after exposureto the maximum temperature of about 150° C. for 10 minutes.Approximately 10 mg of solid material from each example was collected ina pan and weighed. The material was heated at a ramp rate of 10° C./minfrom 30° C. to 300° C. and the heat flow was measured relative to anempty reference pan. The cure exotherm (ΔH) was defined as the totalintegrated area under the curve of the heat flow vs. temperature.

Table 5 shows the exotherm, ΔH₀ (J/g) of virgin material prior heating,the exotherm after heating, ΔHF (J/g) to 150° C. for 10 minutes, and thedegree of cure after heating to 150° C. for 10 minutes. The degree ofcure was defined as:

${{Degree}\mspace{14mu}{of}\mspace{14mu}{Cure}\mspace{14mu}(\%)} = {100 \times \left\lbrack {1 - \left( \frac{\Delta H_{F}}{\Delta H_{0}} \right)} \right\rbrack}$

TABLE 5 Cure exotherm before and after heating to 150° C. for 10 minutesExotherm ΔH_(F) (J/g) Degree of Maximum Exotherm following Cure (%)Temper- ΔH₀ (J/g) exposure to after ature prior to 150° C. for 10 min @Example (° C.) curing 10 minutes 150° C. Ex 1 150 27.1 0 ~100% Ex 2 15017.1 0 ~100% CE 1 150 38.8 5.8  85%

The terms and expressions that have been employed are used as terms ofdescription and not of limitation, and there is no intention in the useof such terms and expressions of excluding any equivalents of thefeatures shown and described or portions thereof, but it is recognizedthat various modifications are possible within the scope of theembodiments of the present disclosure. Thus, it should be understoodthat although the present disclosure has been specifically disclosed byspecific embodiments and optional features, modification and variationof the concepts herein disclosed may be resorted to by those of ordinaryskill in the art, and that such modifications and variations areconsidered to be within the scope of embodiments of the presentdisclosure.

Additional Embodiments

The following exemplary embodiments are provided, the numbering of whichis not to be construed as designating levels of importance:

provides a bonded abrasive article precursor comprising

-   -   a curable composition comprising:        -   a curative component; and        -   one or more resins, wherein the curable composition is            curable in an amount of time in a range of from about 0.1            minutes to about 20 minutes at a temperature of about 25° C.            to about 160° C.; and    -   a plurality of abrasive particles dispersed in the curable        composition.

Embodiment 2 provides the bonded abrasive article precursor ofEmbodiment 1, wherein the curative component is in a range of from about0.1 wt % to about 40 wt % of the curable composition.

Embodiment 3 provides the bonded abrasive article precursor of any oneof Embodiments 1 or 2, wherein the curative component is in a range offrom about 0.1 wt % to about 10 wt % of the curable composition.

Embodiment 4 provides the bonded abrasive article of any one ofEmbodiments 1-3, wherein curative component comprises an acid catalyst,a base catalyst, an amphoteric catalyst, an aliphatic polyamine, anaromatic polyamine, an aromatic polyamide, an alicyclic polyamine, apolyamine, a polyamide, an amino resin, a 9,9-bis(aminophenyl)fluorene,a polyisocyanate, a polyol chain extender, imidazole, a dicyandiamide,or a mixture thereof.

Embodiment 5 provides the bonded abrasive article precursor ofEmbodiment 4, wherein the acid catalyst comprises antimony hexafluoride,a diazonium salt, an idonium salt, a sulfonium salt, a ferrocenium salt,or a mixture thereof.

Embodiment 6 provides the bonded abrasive article precursor of any oneof Embodiments 4 or 5, wherein the base catalyst comprises an imidazole,a dicyandiamide an amine-functional catalyst, or a mixture thereof.

Embodiment 7 provides the bonded abrasive article precursor of any oneof Embodiments 4-6, wherein the 9,9-bis(aminophenyl)fluorene compound ischosen from 9,9-bis(4-aminophenyl)fluorene,4-methyl-9,9-bis(4-aminophenyl)fluorene,4-chloro-9,9-bis(4-aminophenyl)fluorene,2-ethyl-9,9-bis(4-aminophenyl)fluorene,2-iodo-9,9-bis(4-aminophenyl)fluorene,3-bromo-9,9-bis(4-aminophenyl)fluorene,9-(4-methylaminophenyl)-9-(4-ethylaminophenyl)fluorene,1-chloro-9,9-bis(4-aminophenyl)fluorene,2-methyl-9,9-bis(4-aminophenyl)fluorene,2,6-dimethyl-9,9-bis(4-aminophenyl)fluorene,1,5-dimethyl-9,9-bis(4-aminophenyl)fluorene,2-fluoro-9,9-bis(4-aminophenyl)fluorene,1,2,3,4,5,6,7,8-octafluoro-9,9-bis(4-aminophenyl)fluorene,2,7-dinitro-9,9-bis(4-aminophenyl)fluorene,2-chloro-4-methyl-9,9-bis(4-aminophenyl)fluorene,2,7-dichloro-9,9-bis(4-aminophenyl)fluorene,2-acetyl-9,9-bis(4-aminophenyl)fluorene,2-methyl-9,9-bis(4-methylaminophenyl)fluorene,2-chloro-9,9-bis(4-ethylaminophenyl)fluorene,2-t-butyl-9,9-bis(4-methylaminophenyl)fluorene,9,9-bis(3-methyl-4-aminophenyl)fluorene,9-(3-methyl-4-aminophenyl)-9-(3-chloro-4-aminophenyl)fluorene,9-bis(3-methyl-4-aminophenyl)fluorene,9,9-bis(3-ethyl-4-aminophenyl)fluorene,9,9-bis(3-phenyl-4-aminophenyl)fluorene,9,9-bis(3,5-dimethyl-4-methylaminophenyl)fluorene,9,9-bis(3,5-dimethyl-4-aminophenyl)fluorene,dimethyl-4-methylaminophenyl)-9-(3,5-dimethyl-4-aminophenyl)fluorene,9-(3,5-diethyl-4-aminophenyl)-9-(3-methyl-4-aminophenyl)fluorene,1,5-dimethyl-9,9-bis(3,5-dimethyl-4-methylaminophenyl)fluorene,9,9-bis(3,5-diisopropyl-4-aminophenyl)fluorene,9,9-bis(3-chloro-4-aminophenyl)fluorene,9,9-bis(3,5-dichloro-4-aminophenyl)fluorene,9,9-bis(3,5-diethyl-4-methylaminophenyl)fluorene,9,9-bis(3,5-diethyl-4-aminophenyl)fluorene, and a mixture thereof.

Embodiment 8 provides the bonded abrasive article precursor of any oneof Embodiments 4-7, wherein the polyisocyanate is chosen fromdicyclohexylmethane-4,4′-diisocyanate, isophorone diisocyanate,

Embodiment 9 provides the bonded abrasive article precursor of any oneof Embodiments 4-8, wherein the polyol chain extender is chosen fromethylene glycol, a poly(ethylene glycol), diethylene glycol, triethyleneglycol, tetraethylene glycol, propylene glycol, a poly(propyleneglycol), dipropylene glycol, tripropylene glycol, 1,3-propanediol,1,3-butanediol, 1,4-butanediol, neopentyl glycol, 1,6-hexanediol,1,4-cyclohexanedimethanol, or a mixture thereof.

Embodiment 10 provides the bonded abrasive article precursor of any oneof Embodiments 1-9, wherein the one or more resins are in a range offrom about 20 wt % to about 99.9 wt % of the curable composition.

Embodiment 11 provides the bonded abrasive article precursor of any oneof Embodiments 1-10, wherein the one or more resins are in a range offrom about 25 wt % to about 70 wt % of the curable composition.

Embodiment 12 provides the bonded abrasive article precursor of any oneof Embodiments 1-11, wherein the one or more resins comprise an epoxyresin, an acrylated epoxy resin, a polyester polyol, a polyisocyante, apolyol, or a mixture thereof.

Embodiment 13 provides the bonded abrasive article precursor ofEmbodiment 12, wherein the one or more epoxy resins are chosen from adiglycidyl ether of bisphenol F, a low epoxy equivalent weightdiglycidyl ether of bisphenol A, a liquid epoxy novolac, a liquidaliphatic epoxy, a liquid cycloaliphatic epoxy, a1,4-cyclohexandimethanoldiglycidylether,3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexane carboxylate,tetraglycidylmethylenedianiline,N,N,N′,N′-tetraglycidyl-4,4′-methylenebisbenzenamine, a triglycidyl ofpara-aminophenol, N,N,N′,N′-tetraglycidyl-m-xylenediamine, and a mixturethereof.

Embodiment 14 provides the bonded abrasive article precursor of any oneof Embodiments 12 or 13, wherein the acrylated epoxy resin comprises:

-   -   a tetrahydrofurfuryl (THF) (meth)acrylate copolymer component;    -   one or more of the epoxy resins; and    -   one or more hydroxy-functional polyethers.

Embodiment 15 provides the bonded abrasive article precursor ofEmbodiment 14, wherein the THF (meth)acrylate copolymer componentcomprises one or more THF (meth)acrylate monomers, one or more(meth)acrylate ester monomers, and one or more optional cationicallyreactive functional (meth)acrylate monomers.

Embodiment 16 provides the bonded abrasive article precursor of any oneof Embodiments 14 or 15, wherein the THF (meth)acrylate copolymercomponent comprises:

-   -   (A) 40-60 wt % of tetrahydrofurfuryl (meth)acrylate monomers;    -   (B) 40-60 wt % of alkyl (meth)acrylate ester monomers; and    -   (C) 0-10 wt % of cationically reactive functional monomers;    -   wherein the sum of (A), (B), and (C) is 100 wt % of the THFA        copolymer.

Embodiment 17 provides the bonded abrasive article precursor of any oneof Embodiments 14-16, wherein the curable composition comprises: i) fromabout 15 to about 50 parts by weight of the THF (meth)acrylate copolymercomponent; ii) from about 25 to about 50 parts by weight of the one ormore epoxy resins; iii) from about 5 to about 15 parts by weight of theone or more hydroxy-functional polyethers; iv) from about 10 to about 25parts by weight of one or more hydroxyl-containing film-formingpolymers; where the sum of i) to iv) is 100 parts by weight; and v) fromabout 0.1 to about 5 parts by weight of a photoinitiator, relative tothe 100 parts of i) to iv).

Embodiment 18 provides the bonded abrasive article precursor of any oneof Embodiments 14-17, wherein the one or more hydroxy-functionalpolyethers is a liquid.

Embodiment 19 provides the bonded abrasive article precursor of any oneof Embodiments 12 or 18, wherein the polyester polyol comprisespolyglycolic acid, polybutylene succinate,poly(3-hydroxybutyrate-co-3-hydroxyvalerate), polyethyleneterephthalate, polybutylene terephthalate, polytrimethyleneterephthalate, polyethylene naphthalate, poly(1,4-butylene adipate),poly(1,6-hexamethylene adipate), poly(ethylene-adipate), mixturesthereof, or copolymers thereof.

Embodiment 20 provides the bonded abrasive article precursor of any oneof Embodiments 12-19, wherein the curable composition is an epoxycomposition that comprises one or more epoxy resins.

Embodiment 21 provides the bonded abrasive article precursor of any oneof Embodiments 12-20, wherein the curable composition is a polyurethanecomposition.

Embodiment 22 provides the bonded abrasive article precursor of any oneof Embodiments 1-21, wherein the plurality of abrasive particles are ina range of from about 5 wt % to about 80 wt % of the curablecomposition.

Embodiment 23 provides the bonded abrasive article precursor of any oneof Embodiments 1-22, wherein the plurality of abrasive particles are ina range of from about 50 wt % to about 80 wt % of the curablecomposition.

Embodiment 24 provides the bonded abrasive article precursor of any oneof Embodiments 1-23, at least one of the shaped abrasive particles ofthe plurality of abrasive particles comprises shaped abrasive particlesthat are tetrahedral and comprise four faces joined by six edgesterminating at four tips, each one of the four faces contacting three ofthe four faces.

Embodiment 25 provides the bonded abrasive article precursor ofEmbodiment 24, wherein at least one of the four faces is substantiallyplanar.

Embodiment 26 provides the bonded abrasive article precursor ofEmbodiments 24 or 25, wherein at least one of the four faces is concave.

Embodiment 27 provides the bonded abrasive article precursor ofEmbodiment 24, wherein all of the four faces are concave.

Embodiment 28 provides the bonded abrasive article precursor of any oneof Embodiments 24 or 26, wherein at least one of the four faces isconvex.

Embodiment 29 provides the bonded abrasive article precursor ofEmbodiment 24, wherein all of the four faces are convex.

Embodiment 30 provides the bonded abrasive article precursor of any oneof Embodiments 24-29, wherein at least one of the tetrahedral abrasiveparticles has equally-sized edges.

Embodiment 31 provides the bonded abrasive article precursor of any oneof Embodiments 24-30, wherein at least one of the tetrahedral abrasiveparticles has different-sized edges.

Embodiment 32 provides the bonded abrasive article precursor of any oneof Embodiments 1-31, wherein at least one of the abrasive particles ofthe plurality of abrasive particles are a shaped abrasive particlehaving a first side and a second side separated by a thickness t, thefirst side comprises a first face having a triangular perimeter and thesecond side comprises a second face having a triangular perimeter,wherein the thickness t is equal to or smaller than the length of theshortest side-related dimension of the particle.

Embodiment 33 provides the bonded abrasive article precursor ofEmbodiment 32, wherein the shaped abrasive particle further comprises atleast one sidewall connecting the first side and the second side.

Embodiment 34 provides the bonded abrasive article precursor ofEmbodiment 33, wherein the at least one sidewall of the shaped abrasiveparticle is a sloping sidewall.

Embodiment 35 provides the bonded abrasive article precursor of any oneof Embodiments 33 or 34, wherein a draft angle α of the sloping sidewallof the shaped abrasive particle is in a range of from about 95 degreesand about 130 degrees.

Embodiment 36 provides the bonded abrasive article precursor of any oneof Embodiments 32-35, wherein the first face and the second face of theshaped abrasive particle are substantially parallel to each other.

Embodiment 37 provides the bonded abrasive article precursor of any oneof Embodiments 32-36, wherein the first face and the second face of theshaped abrasive particle are substantially non-parallel to each other.

Embodiment 38 provides the bonded abrasive article precursor of any oneof Embodiments 32-37, wherein at least one of the first and the secondface of the shaped abrasive particle are substantially planar.

Embodiment 39 provides the bonded abrasive article precursor of any oneof Embodiments 32-38, wherein at least one of the first and the secondface of the shaped abrasive particle is a non-planar face.

Embodiment 40 provides the bonded abrasive article precursor of any oneof Embodiments 1-39, wherein one or more of the abrasive particles are ashaped abrasive particle comprising a cylindrical body extending betweencircular first and second ends.

Embodiment 41 provides the bonded abrasive article precursor of any oneof Embodiments 1-39, wherein at least one of the abrasive particlescomprises an opening, a concave surface, a convex surface, a groove, aridge, a fractured surface, a low roundness factor, a perimetercomprising one or more corner points having a sharp tip, or acombination thereof.

Embodiment 42 provides the bonded abrasive article precursor of any oneof Embodiments 1-41, wherein at least some of the plurality of abrasiveparticles comprise a ceramic material.

Embodiment 43 provides the bonded abrasive article precursor of any oneof Embodiments 1-42, wherein at least some of the plurality of abrasiveparticles comprise alpha alumina, sol-gel derived alpha alumina, powderderived alumina, or a mixture thereof.

Embodiment 44 provides the bonded abrasive article precursor of any oneof Embodiments 1-43, wherein at least some of the plurality of abrasiveparticles comprise an aluminosilicate, an alumina, a silica, a siliconnitride, a carbon, a glass, a metal, an alumina-phosphorous pentoxide,an alumina-boria-silica, a zirconia, a zirconia-alumina, azirconia-silica, a fused aluminum oxide, a heat-treated aluminum oxide,a ceramic aluminum oxide, a sintered aluminum oxide, a silicon carbidematerial, titanium diboride, boron carbide, tungsten carbide, titaniumcarbide, diamond, cubic boron nitride, garnet, fused alumina-zirconia,cerium oxide, zirconium oxide, titanium oxide, or a combination thereof.

Embodiment 45 provides the bonded abrasive article precursor of any oneof Embodiments 1-44, wherein one or more of the plurality of abrasiveparticles comprises a reaction product of a polymerizable mixtureincluding one or more polymerizable resins.

Embodiment 46 provides the bonded abrasive article precursor ofEmbodiment 45, wherein the one or more polymerizable resins are chosenfrom a phenolic resin, a urea formaldehyde resin, a urethane resin, amelamine resin, an epoxy resin, a bismaleimide resin, a vinyl etherresin, an aminoplast resin, an acrylate resin, an acrylated isocyanurateresin, an isocyanurate resin, an acrylated urethane resin, an acrylatedepoxy resin, an alkyd resin, and mixtures thereof.

Embodiment 47 provides the bonded abrasive article precursor of any oneof Embodiments 45 or 46, wherein the polymerizable mixture furthercomprise at least one of a plasticizer, a catalyst, a cross-linker, asurfactant, a mild abrasive, a pigment, and an antibacterial agent.

Embodiment 48 provides the bonded abrasive article precursor ofEmbodiment 47, wherein the polymerizable resin is in a range of fromabout 35 wt % to about 100 wt % of the polymerizable mixture.

Embodiment 49 provides the bonded abrasive article precursor of any oneof Embodiments 47 or 48, wherein the polymerizable resin is in a rangeof from about 40 wt % to about 95 wt % of the polymerizable mixture.

Embodiment 50 provides the bonded abrasive article precursor of any oneof Embodiments 45-49, wherein the cross-linker is in a range of fromabout 2 wt % to about 15 wt % of the polymerizable mixture.

Embodiment 51 provides the bonded abrasive article precursor of any oneof Embodiments 45-50, wherein the cross-linker is in a range of fromabout 5 wt % to about 10 wt % of the polymerizable mixture.

Embodiment 52 provides the bonded abrasive article precursor of any oneof Embodiments 45-51, wherein the mild abrasive is in a range of from 5wt % to about 65 wt % of the polymerizable mixture.

Embodiment 53 provides the bonded abrasive article precursor of any oneof Embodiments 45-52, wherein the mild abrasive is in a range of from 10wt % to about 20 wt % of the polymerizable mixture.

Embodiment 54 provides the bonded abrasive article precursor of any oneof Embodiments 45-53, wherein the plasticizer is in a range of from 5 wt% to about 40 wt % of the polymerizable mixture.

Embodiment 55 provides the bonded abrasive article precursor of any oneof Embodiments 45-54, wherein the plasticizer is in a range of from 10wt % to about 15 wt % of the polymerizable mixture.

Embodiment 56 provides the bonded abrasive article precursor of any oneof Embodiments 45-55, wherein the catalyst is in a range of from 1 wt %to about 20 wt % of the polymerizable mixture.

Embodiment 57 provides the bonded abrasive article precursor of any oneof Embodiments 45-56, wherein the catalyst is in a range of from 5 wt %to about 10 wt % of the polymerizable mixture.

Embodiment 58 provides the bonded abrasive article precursor of any oneof Embodiments 45-57, wherein the surfactant is in a range of from 1 wt% to about 15 wt % of the polymerizable mixture.

Embodiment 59 provides the bonded abrasive article precursor of any oneof Embodiments 45-58, wherein the surfactant is in a range of from 5 wt% to about 10 wt % of the polymerizable mixture.

Embodiment 60 provides the bonded abrasive article precursor of any oneof Embodiments 45-59, wherein the antimicrobial agent is in a range offrom 5 wt % to about 20 wt % of the polymerizable mixture.

Embodiment 61 provides the bonded abrasive article precursor of any oneof Embodiments 45-60, wherein the antimicrobial agent is in a range offrom 10 wt % to about 15 wt % of the polymerizable mixture.

Embodiment 62 provides the bonded abrasive article precursor of any oneof Embodiments 45-61, wherein the pigment is in a range of from 1 wt %to about 10 wt % of the polymerizable mixture.

Embodiment 63 provides the bonded abrasive article precursor of any oneof Embodiments 45-62, wherein the pigment is in a range of from 3 wt %to about 5 wt % of the polymerizable mixture.

Embodiment 64 provides the bonded abrasive article precursor of any oneof claims 1-63, further comprising crushed abrasive particles.

Embodiment 65 provides the bonded abrasive article precursor ofEmbodiment 64, wherein the crushed abrasive particles are in a range offrom about 5 wt % to about 80 wt % of the curable composition.

Embodiment 66 provides the bonded abrasive article precursor of any oneof Embodiments 64 or 65, wherein the crushed abrasive particles are in arange of from about 20 wt % to about 50 wt % of the curable composition.

Embodiment 67 provides the bonded abrasive article precursor of any oneof Embodiments 1-66, wherein one or more of the plurality of abrasiveparticles are arranged in the curable composition in a predeterminedpattern.

Embodiment 68 provides the bonded abrasive article precursor ofEmbodiment 67, wherein the predetermined pattern comprises a pluralityof circles.

Embodiment 69 provides the bonded abrasive article precursor of any oneof Embodiments 67 or 68, wherein the predetermined pattern comprises aplurality of substantially parallel lines.

Embodiment 70 provides the bonded abrasive article precursor of any oneof Embodiments 1-69, wherein a z-direction rotational angle ofindividual abrasive particles of the plurality of abrasive particles issubstantially the same.

Embodiment 71 provides the bonded abrasive article precursor of any oneof Embodiments 1-70, further comprising a pigment component.

Embodiment 72 provides a bonded abrasive article, comprising a curedproduct of the curable composition of any one of Embodiments 1-71.

Embodiment 73 provides the bonded abrasive article of Embodiment 72,wherein the cured product comprises a cured epoxy network.

Embodiment 74 provides the bonded abrasive article of Embodiment 72,wherein the cured product comprises a polyurethane network and acrylatenetwork, or a combination thereof.

Embodiment 75 provides the bonded abrasive article of any one ofEmbodiments 72-74, wherein the cured product has a first major surfaceand an opposed second major surface each contacting a peripheral sidesurface and a central axis extends through the first and second majorsurfaces.

Embodiment 76 provides the bonded abrasive article of Embodiment 75,wherein the first major surface and the second major surface aredifferent sizes.

Embodiment 77 provides the bonded abrasive article of any one ofEmbodiments 72-76, wherein the plurality of abrasive particles arearranged as one or more layers of abrasive particles.

Embodiment 78 provides the bonded abrasive article of any one ofEmbodiments 72-77, wherein the first major surface and the second majorsurface have a substantially circular profile.

Embodiment 79 provides the bonded abrasive article of any one ofEmbodiments 72-78, further comprising a central aperture extending atleast partially between the first and second major surfaces.

Embodiment 80 provides the bonded abrasive article of Embodiment 79,wherein the central axis extends through the central aperture.

Embodiment 81 provides the bonded abrasive article of any one ofEmbodiments 72-80, wherein the article comprises a reinforcing layer.

Embodiment 82 provides the bonded abrasive article of Embodiment 81,wherein the reinforcing layer comprises a polymeric film, a metal foil,a woven fabric, a knitted fabric, paper, vulcanized fiber, a staplefiber, a continuous fiber, a nonwoven, a foam, a screen, a laminate, andcombinations thereof.

Embodiment 83 provides the bonded abrasive article of any one ofEmbodiments 72-82, wherein the abrasive article is at least one of acut-off wheel, a cut-and-grind wheel, a depressed center grinding wheel,a depressed center cut-off wheel, a reel grinding wheel, a mountedpoint, a tool grinding wheel, a roll grinding wheel, a hot-pressedgrinding wheel, a face grinding wheel, a rail grinding wheel, a grindingcone, a grinding plug, a cup grinding wheel, a gear grinding wheel, acenterless grinding wheel, a cylindrical grinding wheel, an innerdiameter grinding wheel, an outer diameter grinding wheel, and a doubledisk grinding wheel.

Embodiment 84 provides the bonded abrasive article of any one ofEmbodiments 72-83, wherein a diameter of the bonded abrasive article isin a range of from about 2 mm to about 2000 mm.

Embodiment 85 provides the bonded abrasive article of any one ofEmbodiments 72-84, wherein a diameter of the bonded abrasive article isin a range of from about 100 mm to about 1000 mm.

Embodiment 86 provides the bonded abrasive article of any one ofEmbodiments 72-85, wherein water comprises less than about 2 wt % of thebonded abrasive article.

Embodiment 87 provides the bonded abrasive article of any one ofEmbodiments 72-86, wherein a about 80% to about 100% of the reactantsare polymerized.

Embodiment 88 provides a method of making the bonded abrasive article ofany one of Embodiments 72-87, the method comprising curing the curablecomposition of any one of Embodiments 1-71.

Embodiment 89 provides the method of Embodiment 88, wherein the curablecomposition is cured at a temperature in a range of from about 25° C. toabout 160° C.

Embodiment 90 provides the method of any one of Embodiments 88 or 89,wherein the curable composition is cured at a temperature in a range offrom about 100° C. to about 150° C.

Embodiment 91 provides the method of any one of Embodiments 88-90,wherein the curable composition is cured at a temperature of about 160°C. or less.

Embodiment 92 provides the method of any one of Embodiments 88-91,wherein the curable composition is cured for an amount of time in arange of from about 0.5 minutes to about 45 minutes.

Embodiment 93 provides the method of any one of Embodiments 88-92,wherein the curable composition is cured for an amount of time in arange of from about 1 minute to about 10 minutes.

Embodiment 94 provides the method of any one of Embodiments 88-93,wherein the curable composition is disposed in a mold and cured therein.

Embodiment 95 provides the method of Embodiment 94, wherein theplurality of abrasive particles are disposed in an apparatus andreleased into the curable composition disposed in the mold.

Embodiment 96 provides the method of Embodiment 95, wherein theapparatus comprises:

a housing comprising a first apparatus major surface, an opposed secondapparatus major surface, and a peripheral surface connecting the firstapparatus major surface and the second apparatus major surface;

wherein the first apparatus major surface comprises a plurality of holeseach adapted to receive an abrasive particle.

Embodiment 97 provides the method of any one of Embodiments 95 or 96,wherein the first apparatus major surface has a substantially planarprofile.

Embodiment 98 provides the method of any one of Embodiments 95-97,wherein the housing comprises an inlet adapted to connect to a vacuumgenerator.

Embodiment 99 provides the method of any one of Embodiments 95-98,further comprising a magnet aligned with at least one of the holes ofthe first surface.

Embodiment 100 provides the method of Embodiment 99, wherein the magnetis located within the housing.

Embodiment 101 provides the method of any one of Embodiments 95-100,wherein a majority of the holes are substantially the same size.

Embodiment 102 provides the method of any one of Embodiments 95-101,wherein the plurality of holes comprise a first hole and a second hole,wherein a size of at least the first hole and the second hole aredifferent.

Embodiment 103 provides the method of any one of Embodiments 95-102,wherein at least one of the holes has a polygonal shape.

Embodiment 104 provides the method of any one of Embodiments 88-103,further comprising:

contacting the cured composition with a phenolic resin, a vitrifiedbinder, a metallic binder, or a mixture thereof; and

curing the phenolic resin material, the vitrified binder material, themetallic binder material, or a mixture thereof.

Embodiment 105 provides the method of any one of Embodiments 88-104,further comprising exposing the abrasive particles to a magnetic field.

Embodiment 106 provides the method of Embodiment 105, further comprisingrotating the abrasive particles with the magnetic field.

Embodiment 107 provides a method of using the abrasive article of anyone of Embodiments 72-106, comprising:

moving the abrasive article with respect to a surface contactedtherewith, to abrade the surface.

1. An abrasive article comprising: a plurality of shaped abrasiveparticles, each shaped abrasive particle comprising a microparticulatelayer disposed on at least a portion of the outer surface of theabrasive particles, wherein the microparticulate layer comprisesmicroparticles dispersed in a microparticle binder and the abrasiveparticles are shaped abrasive particles; and wherein some of themicroparticles have an aspect ratio greater than 2; and a binder inwhich the plurality of shaped abrasive particles are dispersed.
 2. Theabrasive article of claim 1, wherein a majority of the microparticleshave an aspect ratio between 2 and
 5. 3. The abrasive article of claim1, wherein the microparticles comprise wollastonite.
 4. The abrasivearticle of claim 1, wherein the abrasive article is a bonded abrasivearticle.
 5. (canceled)
 6. (canceled)
 7. The abrasive article of claim 1,wherein the microparticles comprise between about 0.5% and about 4% byweight of each of the shaped abrasive particles.
 8. The abrasive articleof claim 1, wherein the binder is between 0.1 and 1% of each of theshaped abrasive particles, by weight.
 9. (canceled)
 10. The abrasiveparticles of claim 1, wherein the microparticle size ranges from about0.5 μm to about 50 μm.
 11. (canceled)
 12. The abrasive particles ofclaim 1, wherein the abrasive microparticles are made of a differentmaterial relative to the abrasive particles on which the abrasivemicroparticles are disposed.
 13. The abrasive particles of claim 1,wherein the microparticulate layer comprises grinding aidmicroparticles.
 14. (canceled)
 15. The abrasive particles of claim 1,wherein the microparticles comprise at least one of FeS₂, FeS, andFe₂O₃.
 16. The abrasive particles of claim 1, wherein the microparticlescomprise at least one of chlorinated waxes and halide salts.
 17. Theabrasive particles of claim 16, wherein the chlorinated waxes compriseat least one of tetrachloronaphthalene, pentachloronaphthalene, andpolyvinyl chloride.
 18. The abrasive particles of claim 16, wherein thehalide salts comprise at least one of sodium chloride, potassiumcryolite, sodium cryolite, ammonium cryolite, potassiumtetrafluoridoaluminate, sodium tetrafluoridoaluminate, potassiumtetrafluoroborate, sodium tetrafluoroborate, silicon fluorides,potassium chloride, magnesium chloride, and combinations thereof. 19.The abrasive particles of claim 1, wherein the microparticles in themicroparticulate layer are present in amounts of from about 0.1 wt % toabout 10 wt % of the abrasive particles.
 20. The abrasive particles ofclaim 1, wherein the microparticulate layer is disposed on at leastabout 10% to about 90% of an outer surface of the abrasive particles.21. The abrasive particles of claim 1, wherein the microparticle binderis an inorganic binder or an organic binder.
 22. (canceled) 23.(canceled)
 24. The abrasive particles of claim 1, wherein themicroparticulate layer comprises microparticles and a silane dispersedin the binder.
 25. The abrasive article of claim 1, wherein the abrasivearticle is a coated abrasive article, a non-woven abrasive article or abonded abrasive article.
 26. The abrasive article of claim 19, whereinthe abrasive article is a bonded abrasive article.
 27. The abrasivearticle of claim 26, wherein the abrasive article is a mounted point, acut-off wheel, a cut-and-grind wheel, a depressed center grinding wheel,a depressed center cut-off wheel, a reel grinding wheel, a mountedpoint, a tool grinding wheel, a roll grinding wheel, a hot-pressedgrinding wheel, a face grinding wheel, a rail grinding wheel, a grindingcone, a grinding plug, a cup grinding wheel, a gear grinding wheel, acenterless grinding wheel, a cylindrical grinding wheel, an innerdiameter grinding wheel, an outer diameter grinding wheel, a double diskgrinding wheel or abrasive segments.